Displaying publications 61 - 80 of 3479 in total

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  1. Fulltext Oncogenic Roles and Inhibitors of DNMT1, DNMT3A, and DNMT3B in Acute Myeloid Leukaemia
    Wong KK, Lawrie CH, Green TM
    Biomark Insights, 2019;14:1177271919846454.
    PMID: 31105426 DOI: 10.1177/1177271919846454
    Epigenetic alteration has been proposed to give rise to numerous classic hallmarks of cancer. Impaired DNA methylation plays a central role in the onset and progression of several types of malignancies, and DNA methylation is mediated by DNA methyltransferases (DNMTs) consisting of DNMT1, DNMT3A, and DNMT3B. DNMTs are frequently implicated in the pathogenesis and aggressiveness of acute myeloid leukaemia (AML) patients. In this review, we describe and discuss the oncogenic roles of DNMT1, DNMT3A, and DNMT3B in AML. The clinical response predictive roles of DNMTs in clinical trials utilising hypomethylating agents (azacitidine and decitabine) in AML patients are presented. Novel hypomethylating agent (guadecitabine) and experimental DNMT inhibitors in AML are also discussed. In summary, hypermethylation of tumour suppressors mediated by DNMT1 or DNMT3B contributes to the progression and severity of AML (except MLL-AF9 and inv(16)(p13;q22) AML for DNMT3B), while mutation affecting DNMT3A represents an early genetic lesion in the pathogenesis of AML. In clinical trials of AML patients, expression of DNMTs is downregulated by hypomethylating agents while the clinical response predictive roles of DNMT biomarkers remain unresolved. Finally, nucleoside hypomethylating agents have continued to show enhanced responses in clinical trials of AML patients, and novel non-nucleoside DNMT inhibitors have demonstrated cytotoxicity against AML cells in pre-clinical settings.
    Matched MeSH terms: DNA; DNA Modification Methylases; DNA Methylation
  2. Evaluation of genetic diversity of Clinacanthus nutans (Acanthaceaea) using RAPD, ISSR and RAMP markers
    Ismail NZ, Arsad H, Samian MR, Ab Majid AH, Hamdan MR
    Physiol Mol Biol Plants, 2016 Oct;22(4):523-534.
    PMID: 27924125
    Three polymerase chain reaction (PCR) techniques were compared to analyse the genetic diversity of Clinacanthus nutans eight populations in the northern region of Peninsular Malaysia. The PCR techniques were random amplified polymorphic deoxyribonucleic acids (RAPD), inter-simple sequence repeats (ISSR) and random amplified microsatellite polymorphisms (RAMP). Leaf genomic DNA was PCR amplified using 17 RAPD, 8 ISSR and 136 RAMP primers . However, only 10 RAPD primers, 5 ISSR primers and 37 RAMP primers produced reproducible bands. The results were evaluated for polymorphic information content (PIC), marker index (MI) and resolving power (RP). The RAMP marker was the most useful marker compared to RAPD and ISSR markers because it showed the highest average value of PIC (0.25), MI (11.36) and RP (2.86). The genetic diversity showed a high percentage of polymorphism at the species level compared to the population level. Furthermore, analysis of molecular variance revealed that the genetic diversity was higher within populations, as compared to among populations of C. nutans. From the results, the RAMP technique was recommended for the analysis of genetic diversity of C. nutans.
    Matched MeSH terms: DNA; DNA Primers; Random Amplified Polymorphic DNA Technique
  3. Fulltext Genotyping of Salmonella strains isolated from ducks, their rearing and processing environments in Penang, Malaysia, using RAPD
    Adzitey F, Ali GR, Huda N, Ahmad R
    3 Biotech, 2013 Dec;3(6):521-527.
    PMID: 28324423 DOI: 10.1007/s13205-013-0115-7
    Salmonella species are important foodborne pathogens that can cause illness and death in humans. The objective of this study was to determine the genetic relatedness of 115 Salmonella strains isolated from ducks and their environment using random amplified polymorphic deoxyribonucleic acid (RAPD). The analysis of Salmonella strains by RAPD produced DNA fingerprints of different sizes for differentiation purposes, and cluster analysis at a coefficient of 0.85 grouped the Salmonella strains into various clusters and singletons. S. Typhimurium were grouped into nine clusters and ten singletons, S. Hadar were grouped into seven clusters and nine singletons, S. Enteritidis were grouped into four clusters and five singletons, S. Braenderup were grouped into five clusters and four singletons, S. Albany were grouped into two clusters and seven singletons, and S. Derby were grouped into two clusters and four singletons at a coefficient of 0.85 with discriminatory index (D) ranging from 0.879 to 0.957. With the exception of S. Typhimurium strains which were grouped into three major groups (genotypes) by RAPD analysis, the rest were grouped into two major genotypes. RAPD was a useful genotyping tool for determining the genetic relatedness of the duck Salmonella strains. Comparison of the genetic relatedness among foodborne pathogens and their sources of isolation are important to trace their source and possibly the source of human infection.
    Matched MeSH terms: DNA; DNA Fingerprinting; Random Amplified Polymorphic DNA Technique
  4. [A study on identification of edible bird's nests by DNA barcodes]
    Chen YJ, Liu WJ, Chen DN, Chieng SH, Jiang L
    Zhongguo Zhong Yao Za Zhi, 2017 Dec;42(23):4593-4597.
    PMID: 29376257 DOI: 10.19540/j.cnki.cjcmm.20171030.018
    To provide theoretical basis for the traceability and quality evaluation of edible bird's nests (EBNs), the Cytb sequence was applied to identify the origin of EBNs. A total of 39 experiment samples were collected from Malaysia, Indonesia, Vietnam and Thailand. Genomic DNA was extracted for the PCR reaction. The amplified products were sequenced. 36 sequences were downloaded from Gen Bank including edible nest swiftlet, black nest swiftlet, mascarene swiftlet, pacific swiftlet and germain's swiftlet. MEGA 7.0 was used to analyze the distinction of sequences by the method of calculating the distances in intraspecific and interspecific divergences and constructing NJ and UPMGA phylogenetic tree based on Kimera-2-parameter model. The results showed that 39 samples were from three kinds of EBNs. Interspecific divergences were significantly greater than the intraspecific one. Samples could be successfully distinguished by NJ and UPMGA phylogenetic tree. In conclusion, Cytb sequence could be used to distinguish the origin of EBNs and it is efficient for tracing the origin species of EBNs.
    Matched MeSH terms: DNA; DNA Barcoding, Taxonomic*
  5. Revision of Chimarrogale (Lipotyphla: Soricidae) from Vietnam with comments on taxonomy and biogeography of Asiatic water shrews
    Abramov AV, Bannikova AA, Lebedev VS, Rozhnov VV
    Zootaxa, 2017 Feb 15;4232(2):zootaxa.4232.2.5.
    PMID: 28264392 DOI: 10.11646/zootaxa.4232.2.5
    We analyzed the complete mitochondrial cytochrome b (cytb) gene and fragments of four nuclear loci: ApoB, RAG2, IRBP1 and BRCA1. These data allowed us to provide new insights into the diversity of the Asiatic water shrews of Indochina. A new, highly divergent genetic lineage of Chimarrogale was found in southern Vietnam, and this lineage included specimens from the provinces of Kon Tum, Dak Lak, and Lam Dong. Such finding represents the newest and southernmost records of Chimarrogale in Indochina. Morphological analysis classified the specimens from southern Vietnam as C. varennei proper, which is restricted to that region, whereas the polymorphic C. himalayica, which contained at least four cytochrome b haplogroups, occurred in central and northern Vietnam and southern China. This distinct C. varennei lineage closely related to the C. platycephalus + C. leander clade suggests the existence of an unknown glacial refuge in Tay Nguyen Plateau, southern Vietnam. Because the Bornean C. phaeura (i) was sister-group of the rest of Chimarrogale sensu lato and (ii) had a high genetic divergence (~15% for cytochrome b) and geographical isolation, we suggest that C. phaeura be placed into a separate genus, Crossogale Thomas, 1921. This genus should also include C. sumatrana (Sumatra) and C. hantu (Peninsular Malaysia). On those grounds, we propose a new classification system for Asiatic water shrews.
    Matched MeSH terms: DNA, Mitochondrial; Sequence Analysis, DNA*
  6. Fulltext Ancient proteins resolve controversy over the identity of Genyornis eggshell
    Demarchi B, Stiller J, Grealy A, Mackie M, Deng Y, Gilbert T, et al.
    Proc Natl Acad Sci U S A, 2022 Oct 25;119(43):e2109326119.
    PMID: 35609205 DOI: 10.1073/pnas.2109326119
    The realization that ancient biomolecules are preserved in "fossil" samples has revolutionized archaeological science. Protein sequences survive longer than DNA, but their phylogenetic resolution is inferior; therefore, careful assessment of the research questions is required. Here, we show the potential of ancient proteins preserved in Pleistocene eggshell in addressing a longstanding controversy in human and animal evolution: the identity of the extinct bird that laid large eggs which were exploited by Australia's indigenous people. The eggs had been originally attributed to the iconic extinct flightless bird Genyornis newtoni (†Dromornithidae, Galloanseres) and were subsequently dated to before 50 ± 5 ka by Miller et al. [Nat. Commun. 7, 10496 (2016)]. This was taken to represent the likely extinction date for this endemic megafaunal species and thus implied a role of humans in its demise. A contrasting hypothesis, according to which the eggs were laid by a large mound-builder megapode (Megapodiidae, Galliformes), would therefore acquit humans of their responsibility in the extinction of Genyornis. Ancient protein sequences were reconstructed and used to assess the evolutionary proximity of the undetermined eggshell to extant birds, rejecting the megapode hypothesis. Authentic ancient DNA could not be confirmed from these highly degraded samples, but morphometric data also support the attribution of the eggshell to Genyornis. When used in triangulation to address well-defined hypotheses, paleoproteomics is a powerful tool for reconstructing the evolutionary history in ancient samples. In addition to the clarification of phylogenetic placement, these data provide a more nuanced understanding of the modes of interactions between humans and their environment.
    Matched MeSH terms: DNA/genetics; DNA, Ancient
  7. Fulltext G-Quadruplexes as An Alternative Recognition Element in Disease-Related Target Sensing
    Ida J, Chan SK, Glökler J, Lim YY, Choong YS, Lim TS
    Molecules, 2019 Mar 19;24(6).
    PMID: 30893817 DOI: 10.3390/molecules24061079
    G-quadruplexes are made up of guanine-rich RNA and DNA sequences capable of forming noncanonical nucleic acid secondary structures. The base-specific sterical configuration of G-quadruplexes allows the stacked G-tetrads to bind certain planar molecules like hemin (iron (III)-protoporphyrin IX) to regulate enzymatic-like functions such as peroxidase-mimicking activity, hence the use of the term DNAzyme/RNAzyme. This ability has been widely touted as a suitable substitute to conventional enzymatic reporter systems in diagnostics. This review will provide a brief overview of the G-quadruplex architecture as well as the many forms of reporter systems ranging from absorbance to luminescence readouts in various platforms. Furthermore, some challenges and improvements that have been introduced to improve the application of G-quadruplex in diagnostics will be highlighted. As the field of diagnostics has evolved to apply different detection systems, the need for alternative reporter systems such as G-quadruplexes is also paramount.
    Matched MeSH terms: DNA, Catalytic/metabolism; DNA, Catalytic/chemistry
  8. Protocol for tropical bed bug use as forensic tools
    Lim L, Ab Majid AH
    Forensic Sci Int, 2024 Oct;363:112209.
    PMID: 39190955 DOI: 10.1016/j.forsciint.2024.112209
    As blood-feeding insects that feed on human hosts, bed bugs could be used in forensic investigations if they are present at a crime scene with no apparent evidence. This study describes how tropical bed bugs (Cimex hemipterus) can be used as forensic tools to collect valid human DNA samples. Short Tandem Repeat (STR) analysis was performed on collected bed bug samples, whereby the results indicate that the obtained quantities of human DNA are mostly substantial to facilitate a comprehensive genetic profiling process.
    Matched MeSH terms: DNA/analysis; DNA/isolation & purification
  9. Fulltext Shewanella phage encoding a putative anti-CRISPR-like gene represents a novel potential viral family
    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; Sequence Analysis, DNA
  10. Fulltext Design pattern mining using distributed learning automata and DNA sequence alignment
    Esmaeilpour M, Naderifar V, Shukur Z
    PLoS One, 2014;9(9):e106313.
    PMID: 25243670 DOI: 10.1371/journal.pone.0106313
    Over the last decade, design patterns have been used extensively to generate reusable solutions to frequently encountered problems in software engineering and object oriented programming. A design pattern is a repeatable software design solution that provides a template for solving various instances of a general problem.
    Matched MeSH terms: DNA*; Sequence Analysis, DNA/methods*
  11. A nucleotide signature for identification of Aglaia stellatopilosa Pannell
    Ng BL, Omarzuki M, Lau GS, Pannell CM, Yeo TC
    Mol Biotechnol, 2014 Jul;56(7):671-9.
    PMID: 24623047 DOI: 10.1007/s12033-014-9746-0
    Members of the genus Aglaia have been reported to contain bioactive phytochemicals. The genus, belonging to the Meliaceae family, is represented by at least 120 known species of woody trees or shrubs in the tropical rain forest. As some of these species are very similar in their morphology, taxonomic identification can be difficult. A reliable and definitive molecular method which can identify Aglaia to the level of the species will hence be useful in comparing the content of specific bioactive compounds between the species of this genus. Here, we report the analysis of DNA sequences in the internal transcribed spacer (ITS) of the nuclear ribosomal DNA and the observation of a unique nucleotide signature in the ITS that can be used for the identification of Aglaia stellatopilosa. The nucleotide signature consists of nine bases over the length of the ITS sequence (654 bp). This uniqueness was validated in 37 samples identified as Aglaia stellatopilosa by an expert taxonomist, whereas the nucleotide signature was lacking in a selection of other Aglaia species and non-Aglaia genera. This finding suggests that molecular typing could be utilized in the identification of Aglaia stellatopilosa.
    Matched MeSH terms: DNA, Ribosomal/genetics*; DNA, Ribosomal Spacer/genetics*
  12. The mitogenome of Pangasius sutchi (Teleostei, Siluriformes: Pangasiidae)
    Zhao H, Kong X, Zhou C
    Mitochondrial DNA, 2014 Oct;25(5):342-4.
    PMID: 23795847 DOI: 10.3109/19401736.2013.800492
    The Pangasius sutchi is an important ornamental and economic fish in Southeast Asia e.g. Thailand, Malaysia and China. The complete mitochondrial genome sequence of P. sutchi has been sequenced, which contains 22 tRNA genes, 13 protein-coding genes, 2 rRNA genes and a non-coding control region with the total length of 16,522 bp. The gene order and composition are similar to most of other vertebrates. Just like most other vertebrates, the bias of G and C was found in different region/genes statistics results. Most of the genes are encoded on heavy strand, except for eight tRNA and ND6 genes. The mitogenome sequence of P. sutchi would contribute to better understand population genetics, evolution of this lineage.
    Matched MeSH terms: DNA, Mitochondrial/analysis; Sequence Analysis, DNA/methods*
  13. Construction of cDNA library and preliminary analysis of expressed sequence tags from green microalga Ankistrodesmus convolutus Corda
    Thanh T, Chi VT, Abdullah MP, Omar H, Noroozi M, Ky H, et al.
    Mol Biol Rep, 2011 Jan;38(1):177-82.
    PMID: 20354903 DOI: 10.1007/s11033-010-0092-4
    Green microalga Ankistrodesmus convolutus Corda is a fast growing alga which produces appreciable amount of carotenoids and polyunsaturated fatty acids. To our knowledge, this is the first report on the construction of cDNA library and preliminary analysis of ESTs for this species. The titers of the primary and amplified cDNA libraries were 1.1×10(6) and 6.0×10(9) pfu/ml respectively. The percentage of recombinants was 97% in the primary library and a total of 337 out of 415 original cDNA clones selected randomly contained inserts ranging from 600 to 1,500 bps. A total of 201 individual ESTs with sizes ranging from 390 to 1,038 bps were then analyzed and the BLASTX score revealed that 35.8% of the sequences were classified as strong match, 38.3% as nominal and 25.9% as weak match. Among the ESTs with known putative function, 21.4% of them were found to be related to gene expression, 14.4% ESTs to photosynthesis, 10.9% ESTs to metabolism, 5.5% ESTs to miscellaneous, 2.0% to stress response, and the remaining 45.8% were classified as novel genes. Analysis of ESTs described in this paper can be an effective approach to isolate and characterize new genes from A. convolutus and thus the sequences obtained represented a significant contribution to the extensive database of sequences from green microalgae.
    Matched MeSH terms: Sequence Analysis, DNA/methods*; DNA, Complementary/genetics
  14. Durianella, a new gasteroid genus of boletes from Malaysia
    Desjardin DE, Wilson AW, Binder M
    Mycologia, 2009 2 11;100(6):956-61.
    PMID: 19202849
    Hydnangium echinulatum, described originally from a single specimen collected in Malaysia, has been recollected, and based on morphological and molecular characters is recognized as representing a new gasteroid genus of boletes with affinities to the Boletineae, herein named Durianella. Diagnostic features include an epigeous, ovoid, pyramidal-warted, durian fruit-like basidiome with gelatinized glebal locules and a columella that turns indigo blue upon exposure, and subglobose basidiospores with long, curved, thin-walled and collapsible spines. A redescription, phylogenetic analysis and comparison with allied taxa are presented.
    Matched MeSH terms: DNA, Fungal/genetics; DNA, Ribosomal/genetics
  15. Fulltext Molecular epidemiology and phylogenetic analysis of Dengue virus type-1 and 2 isolated in Malaysia
    Chew MH, Rahman MM, Hussin S
    Pak J Med Sci, 2015;31(3):615-20.
    PMID: 26150855 DOI: 10.12669/pjms.313.6340
    Detection of different serotypes of dengue virus and provide information on origin, distribution and genotype of the virus.
    Matched MeSH terms: DNA Viruses
  16. Fulltext Limitations of cytochrome oxidase I for the barcoding of Neritidae (Mollusca: Gastropoda) as revealed by Bayesian analysis
    Chee SY
    Genet. Mol. Res., 2015;14(2):5677-84.
    PMID: 26125766 DOI: 10.4238/2015.May.25.20
    The mitochondrial DNA (mtDNA) cytochrome oxidase I (COI) gene has been universally and successfully utilized as a barcoding gene, mainly because it can be amplified easily, applied across a wide range of taxa, and results can be obtained cheaply and quickly. However, in rare cases, the gene can fail to distinguish between species, particularly when exposed to highly sensitive methods of data analysis, such as the Bayesian method, or when taxa have undergone introgressive hybridization, over-splitting, or incomplete lineage sorting. Such cases require the use of alternative markers, and nuclear DNA markers are commonly used. In this study, a dendrogram produced by Bayesian analysis of an mtDNA COI dataset was compared with that of a nuclear DNA ATPS-α dataset, in order to evaluate the efficiency of COI in barcoding Malaysian nerites (Neritidae). In the COI dendrogram, most of the species were in individual clusters, except for two species: Nerita chamaeleon and N. histrio. These two species were placed in the same subcluster, whereas in the ATPS-α dendrogram they were in their own subclusters. Analysis of the ATPS-α gene also placed the two genera of nerites (Nerita and Neritina) in separate clusters, whereas COI gene analysis placed both genera in the same cluster. Therefore, in the case of the Neritidae, the ATPS-α gene is a better barcoding gene than the COI gene.
    Matched MeSH terms: DNA, Mitochondrial/genetics*; DNA Barcoding, Taxonomic*
  17. Fulltext Utility of 16S rDNA Sequencing for Identification of Rare Pathogenic Bacteria
    Loong SK, Khor CS, Jafar FL, AbuBakar S
    J Clin Lab Anal, 2016 Nov;30(6):1056-1060.
    PMID: 27184222 DOI: 10.1002/jcla.21980
    BACKGROUND: Phenotypic identification systems are established methods for laboratory identification of bacteria causing human infections. Here, the utility of phenotypic identification systems was compared against 16S rDNA identification method on clinical isolates obtained during a 5-year study period, with special emphasis on isolates that gave unsatisfactory identification.

    METHODS: One hundred and eighty-seven clinical bacteria isolates were tested with commercial phenotypic identification systems and 16S rDNA sequencing. Isolate identities determined using phenotypic identification systems and 16S rDNA sequencing were compared for similarity at genus and species level, with 16S rDNA sequencing as the reference method.

    RESULTS: Phenotypic identification systems identified ~46% (86/187) of the isolates with identity similar to that identified using 16S rDNA sequencing. Approximately 39% (73/187) and ~15% (28/187) of the isolates showed different genus identity and could not be identified using the phenotypic identification systems, respectively. Both methods succeeded in determining the species identities of 55 isolates; however, only ~69% (38/55) of the isolates matched at species level. 16S rDNA sequencing could not determine the species of ~20% (37/187) of the isolates.

    CONCLUSION: The 16S rDNA sequencing is a useful method over the phenotypic identification systems for the identification of rare and difficult to identify bacteria species. The 16S rDNA sequencing method, however, does have limitation for species-level identification of some bacteria highlighting the need for better bacterial pathogen identification tools.

    Matched MeSH terms: DNA, Bacterial/genetics*; DNA, Ribosomal/genetics*
  18. Fulltext Escaping introns in COI through cDNA barcoding of mushrooms: Pleurotus as a test case
    Avin FA, Subha B, Tan YS, Braukmann TWA, Vikineswary S, Hebert PDN
    Ecol Evol, 2017 09;7(17):6972-6980.
    PMID: 28904776 DOI: 10.1002/ece3.3049
    DNA barcoding involves the use of one or more short, standardized DNA fragments for the rapid identification of species. A 648-bp segment near the 5' terminus of the mitochondrial cytochrome c oxidase subunit I (COI) gene has been adopted as the universal DNA barcode for members of the animal kingdom, but its utility in mushrooms is complicated by the frequent occurrence of large introns. As a consequence, ITS has been adopted as the standard DNA barcode marker for mushrooms despite several shortcomings. This study employed newly designed primers coupled with cDNA analysis to examine COI sequence diversity in six species of Pleurotus and compared these results with those for ITS. The ability of the COI gene to discriminate six species of Pleurotus, the commonly cultivated oyster mushroom, was examined by analysis of cDNA. The amplification success, sequence variation within and among species, and the ability to design effective primers was tested. We compared ITS sequences to their COI cDNA counterparts for all isolates. ITS discriminated between all six species, but some sequence results were uninterpretable, because of length variation among ITS copies. By comparison, a complete COI sequences were recovered from all but three individuals of Pleurotus giganteus where only the 5' region was obtained. The COI sequences permitted the resolution of all species when partial data was excluded for P. giganteus. Our results suggest that COI can be a useful barcode marker for mushrooms when cDNA analysis is adopted, permitting identifications in cases where ITS cannot be recovered or where it offers higher resolution when fresh tissue is. The suitability of this approach remains to be confirmed for other mushrooms.
    Matched MeSH terms: DNA; DNA Primers; DNA, Complementary; DNA Barcoding, Taxonomic
  19. Fulltext Plant DNA barcodes and assessment of phylogenetic community structure of a tropical mixed dipterocarp forest in Brunei Darussalam (Borneo)
    Heckenhauer J, Abu Salim K, Chase MW, Dexter KG, Pennington RT, Tan S, et al.
    PLoS One, 2017;12(10):e0185861.
    PMID: 29049301 DOI: 10.1371/journal.pone.0185861
    DNA barcoding is a fast and reliable tool to assess and monitor biodiversity and, via community phylogenetics, to investigate ecological and evolutionary processes that may be responsible for the community structure of forests. In this study, DNA barcodes for the two widely used plastid coding regions rbcL and matK are used to contribute to identification of morphologically undetermined individuals, as well as to investigate phylogenetic structure of tree communities in 70 subplots (10 × 10m) of a 25-ha forest-dynamics plot in Brunei (Borneo, Southeast Asia). The combined matrix (rbcL + matK) comprised 555 haplotypes (from ≥154 genera, 68 families and 25 orders sensu APG, Angiosperm Phylogeny Group, 2016), making a substantial contribution to tree barcode sequences from Southeast Asia. Barcode sequences were used to reconstruct phylogenetic relationships using maximum likelihood, both with and without constraining the topology of taxonomic orders to match that proposed by the Angiosperm Phylogeny Group. A third phylogenetic tree was reconstructed using the program Phylomatic to investigate the influence of phylogenetic resolution on results. Detection of non-random patterns of community assembly was determined by net relatedness index (NRI) and nearest taxon index (NTI). In most cases, community assembly was either random or phylogenetically clustered, which likely indicates the importance to community structure of habitat filtering based on phylogenetically correlated traits in determining community structure. Different phylogenetic trees gave similar overall results, but the Phylomatic tree produced greater variation across plots for NRI and NTI values, presumably due to noise introduced by using an unresolved phylogenetic tree. Our results suggest that using a DNA barcode tree has benefits over the traditionally used Phylomatic approach by increasing precision and accuracy and allowing the incorporation of taxonomically unidentified individuals into analyses.
    Matched MeSH terms: DNA, Plant/genetics*; DNA Barcoding, Taxonomic/methods*
  20. Molecular dynamics simulations suggest changes in electrostatic interactions as a potential mechanism through which serine phosphorylation inhibits DNA Polymerase β's activity
    Homouz D, Joyce-Tan KH, Shahir Shamsir M, Moustafa IM, Idriss H
    J Mol Graph Model, 2018 01;79:192.
    PMID: 29223917 DOI: 10.1016/j.jmgm.2017.11.002
    DNA polymerase β is a 39kDa enzyme that is a major component of Base Excision Repair in human cells. The enzyme comprises two major domains, a 31kDa domain responsible for the polymerase activity and an 8kDa domain, which bind ssDNA and has a deoxyribose phosphate (dRP) lyase activity. DNA polymerase β was shown to be phosphorylated in vitro with protein kinase C (PKC) at serines 44 and 55 (S44 and S55), resulting in loss of its polymerase enzymic activity, but not its ability to bind ssDNA. In this study, we investigate the potential phosphorylation-induced structural changes for DNA polymerase β using molecular dynamics. The simulations show drastic conformational changes of the polymerase structure as a result of S44 phosphorylation. Phosphorylation-induced conformational changes transform the closed (active) enzyme structure into an open one. Further analysis of the results points to a key hydrogen bond and newly formed salt bridges as potential drivers of these structural fluctuations. The changes observed with S44/55 and S55 phosphorylation were less dramatic than S44 and the integrity of the H-bond was not compromised. Thus the phosphorylation of S44 is likely the major contributor to structural fluctuations that lead to loss of enzymatic activity.
    Matched MeSH terms: DNA Repair; DNA Replication; DNA, Single-Stranded; DNA Polymerase beta
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