Displaying publications 1 - 20 of 173 in total

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  1. Nakowong P, Chatchawal P, Chaibun T, Boonapatcharoen N, Promptmas C, Buajeeb W, et al.
    Talanta, 2024 Mar 01;269:125495.
    PMID: 38043336 DOI: 10.1016/j.talanta.2023.125495
    Cervical cancer emerges as the third most prevalent types of malignancy among women on a global scale. Cervical cancer is significantly associated with the persistent infection of human papillomavirus (HPV) type 16. The process of diagnosing is crucial in order to prevent the progression of a condition into a malignant state. The early detection of cervical cancer through initial stage screening is of the utmost significance in both the prevention and effective management of this disease. The present detection methodology is dependent on quantitative polymerase chain reaction (qPCR), which necessitates the use of a costly heat cycler instrument. In this study, we report the development of an electrochemical DNA biosensor integrated with an isothermal recombinase polymerase amplification (RPA) reaction for the detection and identification of the high-risk HPV-16 genotype. The electrochemical biosensor exhibited a high degree of specificity and sensitivity, as evidenced by its limit of detection (LOD) of 0.23 copies/μL of HPV-16 DNA. The validity of this electrochemical platform was confirmed through the analysis of 40 cervical tissues samples, and the findings were consistent with those obtained through polymerase chain reaction (PCR) testing. Our straightforward electrochemical detection technology and quick turnaround time at 75 min make the assay suitable for point-of-care testing in low-resource settings.
    Matched MeSH terms: DNA, Viral/analysis; DNA, Viral/genetics
  2. Haqshenas G, Molano M, Phillips S, Balgovind P, Garland SM, Hawkes D, et al.
    Arch Pathol Lab Med, 2024 Mar 01;148(3):353-358.
    PMID: 37226838 DOI: 10.5858/arpa.2022-0317-OA
    CONTEXT.—: Detection of human papillomavirus (HPV) in formalin-fixed, paraffin-embedded (FFPE) tissues may identify the cause of lesions and has value for the development of new diagnostic assays and epidemiologic studies. Seegene Anyplex II assays are widely used for HPV screening, but their performance using FFPE samples has not been fully explored.

    OBJECTIVE.—: To validate Anyplex II HPV HR Detection (Anyplex II, Seegene) using FFPE samples.

    DESIGN.—: We used 248 stored DNA extracts from cervical cancer FFPE samples collected during 2005-2015 that tested HPV positive using the RHA kit HPV SPF10-LiPA25, v1 (SPF10, Labo Biomedical Products) HPV genotyping assay, manufacturer-validated for FFPE samples.

    RESULTS.—: Of the selected 248 samples, 243 were used in our analysis. Consistent with SPF10 genotyping results, Anyplex II detected all 12 oncogenic types and had an overall HPV detection rate of 86.4% (210 of 243 samples). Anyplex II and SPF10 showed very high agreement for the detection of the 2 most important oncogenic genotypes: HPV 16 (219 of 226; 96.9%; 95% CI, 93.7-98.75) and HPV 18 (221 of 226; 97.8%; 95% CI, 94.9-99.3).

    CONCLUSIONS.—: Overall results showed that both platforms produced comparable HPV genotyping results, indicating the suitability of Anyplex II for FFPE samples. The Anyplex II assay has the added convenience of being an efficient, single-well semiquantitative polymerase chain reaction assay. Further optimization of Anyplex II may enhance its performance using FFPE samples by improving the detection limit.

    Matched MeSH terms: DNA, Viral/analysis; DNA, Viral/genetics
  3. Wang H, Zheng K, Wang M, Ma K, Ren L, Guo R, et al.
    Microbiol Spectr, 2024 Feb 06;12(2):e0336723.
    PMID: 38214523 DOI: 10.1128/spectrum.03367-23
    Shewanella is a prevalent bacterial genus in deep-sea environments including marine sediments, exhibiting diverse metabolic capabilities that indicate its significant contributions to the marine biogeochemical cycles. However, only a few Shewanella phages were isolated and deposited in the NCBI database. In this study, we report the isolation and characterization of a novel Shewanella phage, vB_SbaS_Y11, that infects Shewanella KR11 and was isolated from the sewage in Qingdao, China. Transmission electron microscopy revealed that vB_SbaS_Y11 has an icosahedral head and a long tail. The genome of vB_SbaS_Y11 is a linear, double-stranded DNA with a length of 62,799 bp and a G+C content of 46.9%, encoding 71 putative open reading frames. No tRNA genes or integrase-related feature genes were identified. An uncharacterized anti-CRISPR AcrVA2 gene was detected in its genome. Phylogenetic analysis based on the amino acid sequences of whole genomes and comparative genomic analyses indicate that vB_SbaS_Y11 has a novel genomic architecture and shares low similarity to Pseudomonas virus H66 and Pseudomonas phage F116. vB_SbaS_Y11 represents a potential new family-level virus cluster with eight metagenomic assembled viral genomes named Ranviridae.IMPORTANCEThe Gram-negative Shewanella bacterial genus currently includes about 80 species of mostly aquatic Gammaproteobacteria, which were isolated around the globe in a multitude of environments, such as freshwater, seawater, coastal sediments, and the deepest trenches. Here, we present a Shewanella phage vB_SbaS_Y11 that contains an uncharacterized anti-CRISPR AcrVA2 gene and belongs to a potential virus family, Ranviridae. This study will enhance the knowledge about the genome, diversity, taxonomic classification, and global distribution of Shewanella phage populations.
    Matched MeSH terms: DNA, Viral/genetics
  4. Jaapar FN, Parmin NA, Halim NHA, Hashim U, Gopinath SCB, Halim FS, et al.
    Int J Biol Macromol, 2023 Dec 31;253(Pt 2):126745.
    PMID: 37689297 DOI: 10.1016/j.ijbiomac.2023.126745
    Genosensor-based electrodes mediated with nanoparticles (NPs) have tremendously developed in medical diagnosis. Herein, we report a facile, rapid, low cost and highly sensitive biosensing strategy for early detection of HPV 18 using gold-nanoparticles (AuNPs) deposited on micro-IDEs. This study represents surface charge transduction of micro-interdigitated electrodes (micro-IDE) alumina insulated with silica, independent and mini genosensor modified with colloidal gold NPs (AuNPs), and determination of gene hybridization for early detection of cervical cancer. The surface of AuNPs deposited micro-IDE functionalized with optimized 3-aminopropyl-triethoxysilane (APTES) followed by hybridization with deoxyribonucleic acid (DNA) virus to develop DNA genosensor. The results of ssDNA hybridization with the ssDNA target of human papillomavirus (HPV) 18 have affirmed that micro-IDE functionalized with colloidal AuNPs resulted in the lowest detection at 0.529 aM. Based on coefficient regression, micro-IDE functionalized with AuNPs produces better results in the sensitivity test (R2 = 0.99793) than unfunctionalized micro-IDE.
    Matched MeSH terms: DNA, Viral/genetics
  5. Wang H, Ren L, Liang Y, Zheng K, Guo R, Liu Y, et al.
    Microbiol Spectr, 2023 Aug 17;11(4):e0533522.
    PMID: 37272818 DOI: 10.1128/spectrum.05335-22
    Psychrobacter is an important bacterial genus that is widespread in Antarctic and marine environments. However, to date, only two complete Psychrobacter phage sequences have been deposited in the NCBI database. Here, the novel Psychrobacter phage vB_PmaS_Y8A, infecting Psychrobacter HM08A, was isolated from sewage in the Qingdao area, China. The morphology of vB_PmaS_Y8A was characterized by transmission electron microscopy, revealing an icosahedral head and long tail. The genomic sequence of vB_PmaS_Y8A is linear, double-stranded DNA with a length of 40,226 bp and 44.1% G+C content, and encodes 69 putative open reading frames. Two auxiliary metabolic genes (AMGs) were identified, encoding phosphoadenosine phosphosulfate reductase and MarR protein. The first AMG uses thioredoxin as an electron donor for the reduction of phosphoadenosine phosphosulfate to phosphoadenosine phosphate. MarR regulates multiple antibiotic resistance mechanisms in Escherichia coli and is rarely found in viruses. No tRNA genes were identified and no lysogeny-related feature genes were detected. However, many similar open reading frames (ORFs) were found in the host genome, which may indicate that Y8A also has a lysogenic stage. Phylogenetic analysis based on the amino acid sequences of whole genomes and comparative genomic analysis indicate that vB_PmaS_Y8A contains a novel genomic architecture similar only to that of Psychrobacter phage pOW20-A, although at a low similarity. vB_PmaS_Y8A represents a new family-level virus cluster with 22 metagenomic assembled viral genomes, here named Minviridae. IMPORTANCE Although Psychrobacter is a well-known and important bacterial genus that is widespread in Antarctic and marine environments, genetic characterization of its phages is still rare. This study describes a novel Psychrobacter phage containing an uncharacterized antibiotic resistance gene and representing a new virus family, Minviridae. The characterization provided here will bolster current understanding of genomes, diversity, evolution, and phage-host interactions in Psychrobacter populations.
    Matched MeSH terms: DNA, Viral/genetics
  6. Gunasinghe J, Hwang SS, Yam WK, Rahman T, Wezen XC
    J Biomol Struct Dyn, 2023;41(12):5583-5596.
    PMID: 35751129 DOI: 10.1080/07391102.2022.2091659
    High-risk (HR) Human papillomavirus (e.g. HPV16 and HPV18) causes approximately two-thirds of all cervical cancers in women. Although the first and second-generation vaccines confer some protection against individuals, there are no approved drugs to treat HR-HPV infections to-date. The HPV E1 protein is an attractive drug target because the protein is highly conserved across all HPV types and is crucial for the regulation of viral DNA replication. Hence, we used the Random Forest algorithm to construct a Quantitative-Structure Activity Relationship (QSAR) model to predict the potential inhibitors against the HPV E1 protein. Our QSAR classification model achieved an accuracy of 87.5%, area under the receiver operating characteristic curve of 1.00, and F-measure of 0.87 when evaluated using an external test set. We conducted a drug repurposing campaign by deploying the model to screen the Drugbank database. The top three compounds, namely Cinalukast, Lobeglitazone, and Efatutazone were analyzed for their cell membrane permeability, toxicity, and carcinogenicity. Finally, these three compounds were subjected to molecular docking and 200 ns-long Molecular Dynamics (MD) simulations. The predicted binding free energies for the candidates were calculated using the MM-GBSA method. The binding free energies for Cinalukast, Lobeglitazone, and Efatutazone were -37.84 kcal/mol, -25.30 kcal/mol, and -29.89 kcal/mol respectively. Therefore, we propose their chemical scaffolds for future rational design of E1 inhibitors.Communicated by Ramaswamy H. Sarma.
    Matched MeSH terms: DNA, Viral
  7. Low WF, Ngeow YF, Chook JB, Tee KK, Ong SK, Peh SC, et al.
    Expert Rev Mol Med, 2022 Nov 16;25:e11.
    PMID: 36380484 DOI: 10.1017/erm.2022.38
    Hepatitis B virus (HBV) infection led to 66% liver deaths world-wide in year 2015. Thirty-seven per cent of these deaths were the result of chronic hepatitis B (CHB)-associated hepatocellular carcinoma (HCC). Although early diagnosis of HCC improves survival, early detection is rare. Methylation of HBV DNA including covalently closed circular DNA (cccDNA) is more often encountered in HCC cases than those in CHB and cirrhosis. Three typical CpG islands within the HBV genome are the common sites for methylation. The HBV cccDNA methylation affects the viral replication and protein expression in the course of infection and may associate with the disease pathogenesis and HCC development. We review the current findings in HBV DNA methylation that provide insights into its role in HCC diagnosis.
    Matched MeSH terms: DNA, Viral/genetics; DNA, Viral/metabolism
  8. Atchison S, Shilling H, Balgovind P, Machalek DA, Hawkes D, Garland SM, et al.
    J Appl Microbiol, 2021 Nov;131(5):2592-2599.
    PMID: 33942451 DOI: 10.1111/jam.15126
    AIM: Validate the Roche, MagNAPure96 (MP96) nucleic acid extraction platform for Seegene Anyplex II HPV28 (Anyplex28) detection of Human Papillomavirus.

    METHODS AND RESULTS: Comparisons were made for Anyplex28 genotyping from 115 cervical samples extracted on the Hamilton, STARlet and the MP96. Two DNA concentrations were used for the MP96, one matched for sample input to the STARlet and another 5× concentration (laboratory standard). Agreement of HPV detection was 89·8% (κ = 0·798; P = 0·007), with HPV detected in 10 more samples for the MP96. There was a high concordance of detection for any oncogenic HPV genotype (κ = 0·77; P = 0·007) and for any low-risk HPV genotype (κ = 0·85; P = 0·008). DNA extracted at laboratory standard had a lower overall agreement 85·2% (κ = 0·708; P DNA with a higher analytical sensitivity on the Anyplex28.

    SIGNIFICANCE AND IMPACT OF THE STUDY: This analysis supports the use of samples extracted on the MP96 for HPV genotyping using the Anyplex28. Furthermore, an increase in DNA concentration increased analytical sensitivity of the Anyplex28, particularly appropriate for prevalence studies.

    Matched MeSH terms: DNA, Viral/genetics
  9. Zhang W, Liang Y, Zheng K, Gu C, Liu Y, Wang Z, et al.
    BMC Genomics, 2021 Sep 20;22(1):675.
    PMID: 34544379 DOI: 10.1186/s12864-021-07978-4
    BACKGROUND: Marine bacteriophages play key roles in the community structure of microorganisms, biogeochemical cycles, and the mediation of genetic diversity through horizontal gene transfer. Recently, traditional isolation methods, complemented by high-throughput sequencing metagenomics technology, have greatly increased our understanding of the diversity of bacteriophages. Oceanospirillum, within the order Oceanospirillales, are important symbiotic marine bacteria associated with hydrocarbon degradation and algal blooms, especially in polar regions. However, until now there has been no isolate of an Oceanospirillum bacteriophage, and so details of their metagenome has remained unknown.

    RESULTS: Here, we reported the first Oceanospirillum phage, vB_OliS_GJ44, which was assembled into a 33,786 bp linear dsDNA genome, which includes abundant tail-related and recombinant proteins. The recombinant module was highly adapted to the host, according to the tetranucleotides correlations. Genomic and morphological analyses identified vB_OliS_GJ44 as a siphovirus, however, due to the distant evolutionary relationship with any other known siphovirus, it is proposed that this virus could be classified as the type phage of a new Oceanospirivirus genus within the Siphoviridae family. vB_OliS_GJ44 showed synteny with six uncultured phages, which supports its representation in uncultured environmental viral contigs from metagenomics. Homologs of several vB_OliS_GJ44 genes have mostly been found in marine metagenomes, suggesting the prevalence of this phage genus in the oceans.

    CONCLUSIONS: These results describe the first Oceanospirillum phage, vB_OliS_GJ44, that represents a novel viral cluster and exhibits interesting genetic features related to phage-host interactions and evolution. Thus, we propose a new viral genus Oceanospirivirus within the Siphoviridae family to reconcile this cluster, with vB_OliS_GJ44 as a representative member.

    Matched MeSH terms: DNA, Viral/genetics
  10. Capozza P, Lorusso E, Colella V, Thibault JC, Tan DY, Tronel JP, et al.
    Vet Microbiol, 2021 Mar;254:109008.
    PMID: 33582484 DOI: 10.1016/j.vetmic.2021.109008
    Feline leukaemia virus (FeLV) is a retrovirus associated with fatal disease in cats with infection in its progressive form. Although there are numerous reports on the occurrence of FeLV in the feline population worldwide, there is a paucity of data in Asia. In this study, we assessed the circulation of FeLV by ELISA and nested PCR in cats from different countries in Southeast Asia (i.e., Thailand, Malaysia, Singapore, Philippines, Indonesia and Vietnam) and Taiwan during 2017-2018. Forty-seven cats were positive to FeLV by antigen or provirus detection, but 32 samples were considered truly positive on the basis of positive molecular testing. Frequency of occurrence of FeLV proviral DNA ranged from 0% (0/43 positive samples) in Indonesia to 18.5% (22/119 positive samples) in Thailand. A statistically significant association (p < 0.05) was found between country of cats origin, age, lifestyle, abnormal oral mucosa, and FeLV molecular positive results. In-depth studies are needed in other countries in Southeast Asia to elucidate the mosaic of knowledge about FeLV epidemiology.
    Matched MeSH terms: DNA, Viral/genetics
  11. Ngo DB, Chaibun T, Yin LS, Lertanantawong B, Surareungchai W
    Anal Bioanal Chem, 2021 Feb;413(4):1027-1037.
    PMID: 33236225 DOI: 10.1007/s00216-020-03061-1
    The aim of this study was to develop a highly specific electrochemical DNA sensor using functionalized lead sulphide (PbS) quantum dots for hepatitis E virus genotype 3 (HEV3) DNA target detection. Functionalized-PbS quantum dots (QDs) were used as an electrochemical label for the detection of HEV3-DNA target by the technique of square wave anodic stripping voltammetry (SWASV). The functionalized-PbS quantum dots were characterized by UV-vis, FTIR, XRD, TEM and zeta potential techniques. As-prepared, functionalized-PbS quantum dots have an average size of 4.15 ± 1.35 nm. The detection platform exhibited LOD and LOQ values of 1.23 fM and 2.11 fM, respectively. HEV3-DNA target spiked serum is also reported.Graphical abstract.
    Matched MeSH terms: DNA, Viral/blood*; DNA, Viral/genetics
  12. Anpuanandam K, Selvarajah GT, Choy MMK, Ng SW, Kumar K, Ali RM, et al.
    BMC Vet Res, 2021 Jan 06;17(1):9.
    PMID: 33407487 DOI: 10.1186/s12917-020-02700-0
    BACKGROUND: A new domestic cat hepadnavirus (DCH, family Hepadnaviridae) was first reported from whole blood samples of domestic cats in Australia in 2018, and from cat serum samples in Italy in 2019. The pathogenesis of DCH is unknown, but it was reported in cats with viraemia (6.5-10.8%), chronic hepatitis (43%) and hepatocellular carcinoma (28%). Recent reports suggest that DCH resembles the human hepatitis B virus (HBV) and its related hepatopathies. This study aims to detect and characterize DCH among domestic cats in Malaysia. A cross-sectional study was performed on 253 cats, of which 87 had paired blood and liver samples, entailing whole-genome sequencing and phylogenetic analysis of DCH from a liver tissue sample.

    RESULTS: Among the 253 cats included in this study, 12.3% of the whole blood samples tested positive for DCH. The detection rate was significantly higher in pet cats (16.6%, n = 24/145) compared to shelter cats (6.5%, n = 7/108). Liver tissues showed higher a DCH detection rate (14.9%, n = 13/87) compared to blood; 5 out of these 13 cats tested positive for DCH in their paired liver and blood samples. Serum alanine transaminase (ALT) was elevated (> 95 units/L) in 12 out of the 23 DCH-positive cats (52.2%, p = 0.012). Whole-genome sequence analysis revealed that the Malaysian DCH strain, with a genome size of 3184 bp, had 98.3% and 97.5% nucleotide identities to the Australian and Italian strains, respectively. The phylogenetic analysis demonstrated that the Malaysian DCH genome was clustered closely to the Australian strain, suggesting that they belong to the same geographically-determined genetic pool (Australasia).

    CONCLUSIONS: This study provided insights into a Malaysian DCH strain that was detected from a liver tissue. Interestingly, pet cats or cats with elevated ALT were significantly more likely to be DCH positive. Cats with positive DCH detection from liver tissues may not necessarily have viraemia. The impact of this virus on inducing liver diseases in felines warrants further investigation.

    Matched MeSH terms: DNA, Viral/analysis
  13. Charlton MR, Alam A, Shukla A, Dashtseren B, Lesmana CRA, Duger D, et al.
    J Gastroenterol, 2020 Sep;55(9):811-823.
    PMID: 32666200 DOI: 10.1007/s00535-020-01698-4
    Asia has intermediate-to-high prevalence and high morbidity of hepatitis B virus (HBV) infection. The use of guideline-recommended nucleos(t)ide analogs with high barrier to resistance, such as entecavir (ETV), tenofovir disoproxil fumarate (TDF), and tenofovir alafenamide (TAF), is one of the key interventions for curbing HBV infection and associated morbidity in Asia. However, there are some challenges to the use of ETV and TDF; while ETV is associated with high resistance in lamivudine (LAM)-exposed (especially LAM-refractory) patients; bone and renal safety issues are a major concern with TDF. Hence, a panel of twenty-eight expert hepatologists from Asia convened, reviewed the literature, and developed the current expert opinion-based review article for the use of TAF in the resource-constrained settings in Asia. This article provides a comprehensive review of two large, phase 3, double-blind, randomized controlled trials of TAF versus TDF in HBeAg-negative (study 0108) and HBeAg-positive (study 0110) chronic HBV patients (> 70% Asians). These studies revealed as follows: (1) non-inferiority for the proportion of patients who had HBV DNA
    Matched MeSH terms: DNA, Viral
  14. Saville M, Hawkes D, Keung M, Ip E, Silvers J, Sultana F, et al.
    J Clin Virol, 2020 06;127:104375.
    PMID: 32361328 DOI: 10.1016/j.jcv.2020.104375
    BACKGROUND: In the last decade, human papillomavirus (HPV) testing has been evaluated extensively for cervical screening, with studies finding increased sensitivity compared to cytology. Another advantage of HPV based-screening is the ability to test vaginal samples that can be collected by women themselves. Self-collection has the potential to extend cervical screening coverage by increasing participation rates, particularly among women who are under-screened or have never screened. This could have a significant impact on cervical cancer prevention, as the majority of invasive cervical cancer cases occur among under-screened women. Both the Netherlands and Australia have transitioned their national programs from cytology to HPV as the primary screening test and both countries include a pathway for self-collection.

    OBJECTIVES: We evaluated the relative sensitivity for HPV detection of self-collection compared with practitioner-collected cervical specimens in the context of the Australian National Cervical Screening Program (NCSP).

    STUDY DESIGN: 303 women aged ≥18 years attending a single tertiary referral centre took their own sample using a flocked-swab, and then had a practitioner-collected sample taken at colposcopy. All samples were tested at a single laboratory on the six PCR-based HPV assays which can be utilised in the NCSP; Roche cobas 4800 and cobas, Abbott RealTime, BD Onclarity, Cepheid Xpert, and Seegene Anyplex.

    RESULTS: HPV16/18 results had high observed agreement between self- and practitioner-collected samples on all assays (range: 0.94-0.99), with good agreement for non-HPV16/18 oncogenic HPV types (range: 0.64-0.73).

    CONCLUSIONS: Self-collection for HPV-based cervical screening shows good concordance and relative sensitivity when compared to practitionercollected samples across assays in the NCSP.

    Matched MeSH terms: DNA, Viral/isolation & purification
  15. Gane EJ, Charlton MR, Mohamed R, Sollano JD, Tun KS, Pham TTT, et al.
    J Viral Hepat, 2020 05;27(5):466-475.
    PMID: 31785182 DOI: 10.1111/jvh.13244
    Asia has an intermediate-to-high prevalence of and high morbidity and mortality from hepatitis B virus (HBV) infection. Optimization of diagnosis and initiation of treatment is one of the crucial strategies for lowering disease burden in this region. Therefore, a panel of 24 experts from 10 Asian countries convened, and reviewed the literature, to develop consensus guidance on diagnosis and initiation of treatment of HBV infection in resource-limited Asian settings. The panel proposed 11 recommendations related to diagnosis, pre-treatment assessment, and indications of therapy of HBV infection, and management of HBV-infected patients with co-infections. In resource-limited Asian settings, testing for hepatitis B surface antigen may be considered as the primary test for diagnosis of HBV infection. Pre-treatment assessments should include tests for complete blood count, liver and renal function, hepatitis B e-antigen (HBeAg), anti-HBe, HBV DNA, co-infection markers and assessment of severity of liver disease. Noninvasive tests such as AST-to-platelet ratio index, fibrosis score 4 or transient elastography may be used as alternatives to liver biopsy for assessing disease severity. Considering the high burden of HBV infection in Asia, the panel adopted an aggressive approach, and recommended initiation of antiviral therapy in all HBV-infected, compensated or decompensated cirrhotic individuals with detectable HBV DNA levels, regardless of HBeAg status or alanine transaminase levels. The panel also developed a simple algorithm for guiding the initiation of treatment in noncirrhotic, HBV-infected individuals. The recommendations proposed herein, may help guide clinicians, to optimize the diagnosis and improvise the treatment rates for HBV infection in Asia.
    Matched MeSH terms: DNA, Viral/blood
  16. Liew PS, Tan TH, Wong YC, Sim EUH, Lee CW, Narayanan K
    ACS Synth Biol, 2020 04 17;9(4):804-813.
    PMID: 32196315 DOI: 10.1021/acssynbio.9b00478
    TelN and tos are a unique DNA linearization unit isolated from bacteriophage N15. While being transferable, the TelN cleaving-rejoining activities remained stable to function on tos in both bacterial and mammalian environments. However, TelN contribution in linear plasmid replication in mammalian cells remains unknown. Herein, we investigated the association of TelN in linear tos-containing DNA (tos-DNA) replication in mammalian cells. Additionally, the mammalian origin of replication (ori) that is well-known to initiate the replication event of plasmid vectors was also studied. In doing so, we identified that both TelN and mammalian initiation sites were essential for the replication of linear tos-DNA, determined by using methylation sensitive DpnI/MboI digestion and polymerase chain reaction (PCR) amplification approaches. Furthermore, we engineered the linear tos-DNA to be able to retain in mammalian cells using S/MAR technology. The resulting S/MAR containing tos-DNA was robust for at least 15 days, with (1) continuous tos-DNA replication, (2) correct splicing of gene transcripts, and (3) stable exogenous gene expression that was statistically comparable to the endogenous gene expression level. Understanding the activities of TelN and tos in mammalian cells can potentially provide insights for adapting this simple DNA linearization unit in developing novel genetic engineering tools, especially to the eukaryotic telomere/telomerase study.
    Matched MeSH terms: DNA, Viral/genetics; DNA, Viral/metabolism; DNA, Viral/chemistry
  17. Tan LP, Tan GW, Sivanesan VM, Goh SL, Ng XJ, Lim CS, et al.
    Int J Cancer, 2020 04 15;146(8):2336-2347.
    PMID: 31469434 DOI: 10.1002/ijc.32656
    Nasopharyngeal carcinoma (NPC) is originated from the epithelial cells of nasopharynx, Epstein-Barr virus (EBV)-associated and has the highest incidence and mortality rates in Southeast Asia. Late presentation is a common issue and early detection could be the key to reduce the disease burden. Sensitivity of plasma EBV DNA, an established NPC biomarker, for Stage I NPC is controversial. Most newly reported NPC biomarkers have neither been externally validated nor compared to the established ones. This causes difficulty in planning for cost-effective early detection strategies. Our study systematically evaluated six established and four new biomarkers in NPC cases, population controls and hospital controls. We showed that BamHI-W 76 bp remains the most sensitive plasma biomarker, with 96.7% (29/30), 96.7% (58/60) and 97.4% (226/232) sensitivity to detect Stage I, early stage and all NPC, respectively. Its specificity was 94.2% (113/120) against population controls and 90.4% (113/125) against hospital controls. Diagnostic accuracy of BamHI-W 121 bp and ebv-miR-BART7-3p were validated. Hsa-miR-29a-3p and hsa-miR-103a-3p were not, possibly due to lower number of advanced stage NPC cases included in this subset. Decision tree modeling suggested that combination of BamHI-W 76 bp and VCA IgA or EA IgG may increase the specificity or sensitivity to detect NPC. EBNA1 99 bp could identify NPC patients with poor prognosis in early and advanced stage NPC. Our findings provided evidence for improvement in NPC screening strategies, covering considerations of opportunistic screening, combining biomarkers to increase sensitivity or specificity and testing biomarkers from single sampled specimen to avoid logistic problems of resampling.
    Matched MeSH terms: DNA, Viral/blood*
  18. Jeningsih, Tan LL, Ulianas A, Heng LY, Mazlan NF, Jamaluddin ND, et al.
    Sensors (Basel), 2020 Mar 25;20(7).
    PMID: 32218202 DOI: 10.3390/s20071820
    A DNA micro-optode for dengue virus detection was developed based on the sandwich hybridization strategy of DNAs on succinimide-functionalized poly(n-butyl acrylate) (poly(nBA-NAS)) microspheres. Gold nanoparticles (AuNPs) with an average diameter of ~20 nm were synthesized using a centrifugation-based method and adsorbed on the submicrometer-sized polyelectrolyte-coated poly(styrene-co-acrylic acid) (PSA) latex particles via an electrostatic method. The AuNP-latex spheres were attached to the thiolated reporter probe (rDNA) by Au-thiol binding to functionalize as an optical gold-latex-rDNA label. The one-step sandwich hybridization recognition involved a pair of a DNA probe, i.e., capture probe (pDNA), and AuNP-PSA reporter label that flanked the target DNA (complementary DNA (cDNA)). The concentration of dengue virus cDNA was optically transduced by immobilized AuNP-PSA-rDNA conjugates as the DNA micro-optode exhibited a violet hue upon the DNA sandwich hybridization reaction, which could be monitored by a fiber-optic reflectance spectrophotometer at 637 nm. The optical genosensor showed a linear reflectance response over a wide cDNA concentration range from 1.0 × 10-21 M to 1.0 × 10-12 M cDNA (R2 = 0.9807) with a limit of detection (LOD) of 1 × 10-29 M. The DNA biosensor was reusable for three consecutive applications after regeneration with mild sodium hydroxide. The sandwich-type optical biosensor was well validated with a molecular reverse transcription polymerase chain reaction (RT-PCR) technique for screening of dengue virus in clinical samples, e.g., serum, urine, and saliva from dengue virus-infected patients under informed consent.
    Matched MeSH terms: DNA, Viral/isolation & purification*; DNA, Viral/chemistry
  19. Mahmoodi P, Rezayi M, Rasouli E, Avan A, Gholami M, Ghayour Mobarhan M, et al.
    J Nanobiotechnology, 2020 Jan 13;18(1):11.
    PMID: 31931815 DOI: 10.1186/s12951-020-0577-9
    BACKGROUND: In several years ago, infection with human papillomaviruses (HPVs), have been prevalent in the worlds especially HPV type 18, can lead to cervical cancer. Therefore, rapid, accurate, and early diagnosis of HPV for successful treatment is essential. The present study describes the development of a selective and sensitive electrochemical biosensor base on DNA, for early detection of HPV-18. For this purpose, a nanocomposite of reduced graphene oxide (rGO) and multiwalled carbon nanotubes (MWCNTs) were electrodeposited on a screen-printed carbon electrode (SPCE). Then, Au nanoparticles (AuNPs) were dropped on a modified SPCE. Subsequently, single strand DNA (ssDNA) probe was immobilized on the modified electrode. The link attached between AuNPs and probe ssDNA provided by L-cysteine via functionalizing AuNPs (Cys-AuNPs). The differential pulse voltammetry (DPV) assay was also used to electrochemical measurement. The measurement was based on the oxidation signals of anthraquninone-2-sulfonic acid monohydrate sodium salt (AQMS) before and after hybridization between the probe and target DNA.

    RESULTS: The calibration curve showed a linear range between 0.01 fM to 0.01 nM with a limit of detection 0.05 fM. The results showed that the optimum concentration for DNA probe was 5 µM. The good performance of the proposed biosensor was achieved through hybridization of DNA probe-modified SPCE with extracted DNA from clinical samples.

    CONCLUSIONS: According to the investigated results, this biosensor can be introduced as a proprietary, accurate, sensitive, and rapid diagnostic method of HPV 18 in the polymerase chain reaction (PCR) of real samples.

    Matched MeSH terms: DNA, Viral/analysis*
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