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  1. Tee LK, Ling CS, Chua MJ, Abdullah S, Rosli R, Chowdhury EH
    Plasmid, 2011 Oct;66(1):38-46.
    PMID: 21419794 DOI: 10.1016/j.plasmid.2011.03.001
    Plasmid DNA is one of the indispensable components in molecular biology research and a potential biomaterial for gene therapy and DNA vaccination. Both quality and quantity of extracted plasmid DNA are of the great interests in cloning and subsequent expression of genes in vitro and in vivo for basic research and therapeutic interventions. Bacteria with extremely short generation times are the valuable source of plasmid DNA that can be isolated through a number of existing techniques. However, the current methods have some limitations in isolating high quality plasmid DNA since the multimeric plasmid which is believed to be more efficiently transcribed by RNA polymerase than the monomeric form, is almost lost during the extraction process. Recently, we developed a rapid isolation technique for multimeric plasmid based on generation of a 'protein aggregate' using a zwitterionic detergent and alkali. Here we have investigated the roles of different parameters in the whole extraction process to optimise the production of high quality multimeric plasmid DNA. Moreover, we have showed the advantageous effects of nanoparticles to effectively sediment the 'protein aggregate' for smooth elution of multimeric plasmid DNA from it. Finally, quality assessment study has revealed that the isolated multimeric DNA is at least 10 times more transcriptionally active than the monomeric form isolated by the commercially available Qiaget kit.
    Matched MeSH terms: DNA, Bacterial/genetics; DNA, Bacterial/isolation & purification*
  2. Balakrishnan KN, Abdullah AA, Bala JA, Jesse FFA, Abdullah CAC, Noordin MM, et al.
    Virol J, 2020 Oct 27;17(1):164.
    PMID: 33109247 DOI: 10.1186/s12985-020-01436-5
    BACKGROUND: Cytomegalovirus (CMV) is an opportunistic pathogen that causes severe complications in congenitally infected newborns and non-immunocompetent individuals. Developing an effective vaccine is a major public health priority and current drugs are fronting resistance and side effects on recipients. In the present study, with the aim of exploring new strategies to counteract CMV replication, several anti-CMV siRNAs targeting IE2 and DNA polymerase gene regions were characterized and used as in combinations for antiviral therapy.

    METHODS: The rat embryo fibroblast (REF) cells were transfected with multi siRNA before infecting with CMV strain ALL-03. Viral growth inhibition was measured by tissue culture infectious dose (TCID50), cytopathic effect (CPE) and droplet digital PCR (ddPCR) while IE2 and DNA polymerase gene knockdown was determined by real-time PCR. Ganciclovir was deployed as a control to benchmark the efficacy of antiviral activities of respective individual siRNAs.

    RESULTS: There was no significant cytotoxicity encountered for all the combinations of siRNAs on REF cells analyzed by MTT colorimetric assay (P > 0.05). Cytopathic effects (CPE) in cells infected by RCMV ALL-03 had developed significantly less and at much slower rate compared to control group. The expression of targeted genes was downregulated successfully resulted in significant reduction (P DNA copies (dpb + dpc: 79%, 68%; dpb + ie2b: 68%, 60%; dpb + dpc + ie2b: 48%, 42%). Flow cytometry analysis showed a greater percentage of viable and early apoptosis of combined siRNAs-treated cells compared to control group. Notably, the siRNAs targeting gene regions were sequenced and mutations were not encountered, thereby avoiding the formation of mutant with potential resistant viruses.

    CONCLUSIONS: In conclusion. The study demonstrated a tremendous promise of innovative approach with the deployment of combined siRNAs targeting at several genes simultaneously with the aim to control CMV replication in host cells.

    Matched MeSH terms: DNA; DNA-Directed DNA Polymerase
  3. Sanders KL, Malhotra A, Thorpe RS
    J Evol Biol, 2004 Jul;17(4):721-31.
    PMID: 15271071
    We analyse molecular and phenotypic evolution in a group of taxonomically problematic Indomalayan pitvipers, the Trimeresurus sumatranus group. Mitochondrial DNA sequencing provides a well-resolved phylogeny, with each species representing a distinct lineage. Multivariate morphological analysis reveals a high level of phenotypic differentiation, which is congruent between the sexes but does not reflect phylogenetic history. An adaptive explanation for the observed pattern of differentiation is supported by independent contrasts analysis, which shows significant correlations between current ecology and the characters that most account for the variation between taxa, including those that are presently used to identify the species. Reduced precipitation and altitude, and increased temperature, are correlated with higher numbers of scales on the head, body and tail. It is hypothesized that scale number plays an important role in heat and water exchange by influencing the area of exposed of interstitial skin, and that colour pattern variation reflects selection pressures involving camouflage and thermoregulation. Ecological convergence in traits used for classification is found to have important implications for species identification where taxa are distributed over varying environments.
    Matched MeSH terms: DNA, Mitochondrial/genetics; Sequence Analysis, DNA
  4. A Talip B, Snelling WJ, Sleator RD, Lowery C, Dooley JSG
    BMC Microbiol, 2018 11 26;18(1):196.
    PMID: 30477427 DOI: 10.1186/s12866-018-1335-0
    BACKGROUND: The field of diagnostics continues to advance rapidly with a variety of novel approaches, mainly dependent upon high technology platforms. Nonetheless much diagnosis, particularly in developing countries, still relies upon traditional methods such as microscopy. Biological material, particularly nucleic acids, on archived glass slides is a potential source of useful information both for diagnostic and epidemiological purposes. There are significant challenges faced when examining archived samples in order that an adequate amount of amplifiable DNA can be obtained. Herein, we describe a model system to detect low numbers of bacterial cells isolated from glass slides using (laser capture microscopy) LCM coupled with PCR amplification of a suitable target.

    RESULTS: Mycobacterium smegmatis was used as a model organism to provide a proof of principle for a method to recover bacteria from a stained sample on a glass slide using a laser capture system. Ziehl-Neelsen (ZN) stained cells were excised and catapulted into tubes. Recovered cells were subjected to DNA extraction and pre-amplified with multiple displacement amplification (MDA). This system allowed a minimum of 30 catapulted cells to be detected following a nested real-time PCR assay, using rpoB specific primers. The combination of MDA and nested real-time PCR resulted in a 30-fold increase in sensitivity for the detection of low numbers of cells isolated using LCM.

    CONCLUSIONS: This study highlights the potential of LCM coupled with MDA as a tool to improve the recovery of amplifiable nucleic acids from archived glass slides. The inclusion of the MDA step was essential to enable downstream amplification. This platform should be broadly applicable to a variety of diagnostic applications and we have used it as a proof of principle with a Mycobacterium sp. model system.

    Matched MeSH terms: DNA, Bacterial/genetics; DNA, Bacterial/isolation & purification*
  5. Phong SF, Hair-Bejo M, Omar AR, Aini I
    Avian Dis, 2003 Jan-Mar;47(1):154-62.
    PMID: 12713171
    The VP2 hypervariable region of P97/302 local infectious bursal disease virus (IBDV) isolate was amplified by the reverse transcriptase (RT) nested polymerase chain reaction (PCR) and cloned. This region of P97/302 local isolate was sequenced and compared with eight other reported IBDV sequences. The result showed that P97/302 IBDV was most identical to the reported very virulent IBDV strains because it has amino acid substitutions at positions 222, 256, 294, and 299, which encode alanine, isoleucine, isoleucine, and serine, respectively. This region can be digested with restriction enzymes of Taq1, Sty1, Ssp1 but not with Sac1. The P97/302 isolate was then used for the optimization of RT nested PCR enzyme-linked immunosorbent assay (ELISA). The RT nested PCR ELISA was able to detect 10(-4) dilution of the infected bursa homogenates and was 10 times more sensitive when compared with the agarose gel detection method. The RT nested PCR ELISA can detect up to 0.48 ng of the PCR product. The specificity of this nested PCR ELISA was also high (100%).
    Matched MeSH terms: Sequence Analysis, DNA; DNA, Complementary/genetics
  6. 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
  7. Nour El Huda AR, Norsidah KZ, Nabil Fikri MR, Hanisah MN, Kartini A, Norlelawati AT
    Psychiatry Clin Neurosci, 2018 Apr;72(4):266-279.
    PMID: 29160620 DOI: 10.1111/pcn.12622
    AIM: This study examined catechol-O-methyltransferase (COMT) DNA methylation in the peripheral blood of schizophrenia patients and also in healthy controls to investigate its potential use as a peripheral biomarker of schizophrenia and its relations with the clinical variables of schizophrenia patients.

    METHODS: We examined the DNA methylation levels of COMT using genomic DNA from the peripheral blood of schizophrenia patients (n = 138) and healthy control participants (n = 132); all were Malaysian Malays. The extracted DNA was bisulfite converted, and the percentage methylation ratio value was calculated based on the results following a MethyLight protocol analysis.

    RESULTS: The percentage methylation ratio of COMT was lower in schizophrenia than it was in the healthy controls (P DNA methylation rate was lower in patients receiving atypical antipsychotics (P = 0.004) and risperidone (P = 0.049) as compared to typical antipsychotics. The Excitement and Depressed subdomains of the Positive and Negative Syndrome Scale were inversely related (P DNA methylation.

    CONCLUSION: Our results suggested that the methylation level was affected by the severity of the clinical symptoms of schizophrenia and might also be influenced by pharmacological treatment. The epigenetic alteration of COMT in the peripheral blood could be a potential peripheral biomarker of schizophrenia.

    Matched MeSH terms: DNA Methylation/drug effects; DNA Methylation/physiology*
  8. Yap NJ, Vythilingam I, Hoh BP, Goh XT, Muslim A, Ngui R, et al.
    Parasit Vectors, 2018 Dec 05;11(1):626.
    PMID: 30518419 DOI: 10.1186/s13071-018-3234-5
    BACKGROUND: The merozoite surface protein-1 (MSP-1) gene encodes for a leading malaria vaccine candidate antigen. However, its extensive polymorphic nature represents a major obstacle to the development of a protective vaccine. Previously, a pilot study was carried out to explore the sequence variation of the C-terminal 42 kDa fragment within P. knowlesi MSP-1 gene (PkMSP-142) based on 12 clinical samples; however, further study on an adequate sample size is vital in estimating the genetic diversity of the parasite population.

    METHODS: In the present study, we included a larger sample size of P. knowlesi (83 samples) covering eight states of Malaysia to determine the genetic polymorphism, natural selection and haplotype groups of the gene fragment coding PkMSP-142. The region flanking PkMSP-142 was amplified by PCR and directly sequenced. Genetic diversity, haplotype diversity, population genetic differentiation and natural selection were determined in order to study the polymorphic characteristic of PkMSP-142.

    RESULTS: A high level of genetic diversity (Hd = 0.970 ± 0.007; л = 0.01079 ± 0.00033) was observed among the 83 P. knowlesi samples, confirming the extensive genetic polymorphism exhibited among the P. knowlesi population found in Malaysia. A total of 18 distinct haplotypes with 17 amino acid changes were identified, whereby 15 were new haplotypes. High population differentiation values were observed within samples from Peninsular Malaysia and Malaysian Borneo. The 42 kDa fragments of P. knowlesi from Malaysian Borneo were found to be acting on balancing selection whilst purifying selection was suggested to act on isolates from Peninsular Malaysia. The separation of PkMSP-142 haplotypes into two main groups based on geographical separation has further supported the existence of two distinct P. knowlesi lineages.

    CONCLUSIONS: A high level of genetic diversity was observed among PkMSP-142 in Malaysia, whereby most of the polymorphisms were found within the 33 kDa region. Taken together, these data will be useful in order to understand the nature of P. knowlesi population in Malaysia as well as the design and development of a MSP-142 based knowlesi malaria vaccine.

    Matched MeSH terms: DNA, Protozoan/genetics; Sequence Analysis, DNA
  9. Lau TTV, Tan JMA, Puthucheary SD, Puah SM, Chua KH
    Braz J Microbiol, 2020 Sep;51(3):909-918.
    PMID: 32067209 DOI: 10.1007/s42770-020-00239-8
    Aeromonas dhakensis is an emergent human pathogen with medical importance. This study was aimed to determine the sequence types (STs), genetic diversity, and phylogenetic relationships of different clinical sources of 47 A. dhakensis from Malaysia using multilocus sequence typing (MLST), goeBURST, and phylogenetic analyses. The analysis of a concatenated six-gene tree with a nucleotide length of 2994 bp based on six housekeeping genes (gyrB, groL, gltA, metG, ppsA, and recA) and independent analyses of single gene fragments was performed. MLST was able to group 47 A. dhakensis from our collection into 36 STs in which 34 STs are novel STs. The most abundant ST521 consisted of five strains from peritoneal fluid and two strains from stools. Comparison of 62 global A. dhakensis was carried out via goeBURST; 94.4% (34/36) of the identified STs are novel and unique in Malaysia. Two STs (111 and 541) were grouped into clonal complexes among our strains and 32 STs occurred as singletons. Single-gene phylogenetic trees showed varying topologies; groL and rpoD grouped all A. dhakensis into a tight-cluster with bootstrap values of 100% and 99%, respectively. A poor phylogenetic resolution encountered in single-gene analyses was buffered by the multilocus phylogenetic tree that offered high discriminatory power (bootstrap value = 100%) in resolving all A. dhakensis from A. hydrophila and delineating the relationship among other taxa. Genetic diversity analysis showed groL as the most conserved gene and ppsA as the most variable gene. This study revealed novel STs and high genetic diversity among clinical A. dhakensis from Malaysia.
    Matched MeSH terms: DNA, Bacterial/genetics; Sequence Analysis, DNA
  10. Zong Z, Wang X, Deng Y, Zhou T
    J Med Microbiol, 2012 Oct;61(Pt 10):1483-1484.
    PMID: 22820689 DOI: 10.1099/jmm.0.041525-0
    A previously healthy Chinese male returned from working in the Malaysian jungle with a fever. A blood culture grew Gram-negative bacilli that were initially identified as Burkholderia cepacia by the VITEK 2 system but were subsequently found to be Burkholderia pseudomallei by partial sequencing of the 16S rRNA gene. The identification of B. pseudomallei using commercially available automated systems is problematic and clinicians in non-endemic areas should be aware of the possibility of melioidosis in patients with a relevant travel history and blood cultures growing Burkholderia spp.
    Matched MeSH terms: DNA, Bacterial/classification; DNA, Bacterial/genetics
  11. Caillaud A, de la Iglesia P, Campàs M, Elandaloussi L, Fernández M, Mohammad-Noor N, et al.
    Toxicon, 2010 Feb-Mar;55(2-3):633-7.
    PMID: 19631680 DOI: 10.1016/j.toxicon.2009.07.016
    Protein phosphatase inhibition assay (PPIA), Neuroblastoma cell-based assay (Neuro-2a CBA) and LC-MS/MS analysis revealed for the first time the production of okadaic acid (OA) by a Prorocentrum rhathymum strain. Low amounts of OA were detected by LC-MS/MS analysis. Inhibition of PP2A activity and a weak toxicity to the Neuro-2a CBA were also observed.
    Matched MeSH terms: DNA/genetics; DNA/chemistry
  12. Anthony C, Mahmud R, Lau YL, Syedomar SF, Sri La Sri Ponnampalavanar S
    Trop Biomed, 2013 Sep;30(3):459-66.
    PMID: 24189676 MyJurnal
    Battling malaria will be a persistent struggle without the proper means to diagnose the parasitic infection. However, the inherent limitations of microscopy, the conventional method of diagnosing malaria, affect the accuracy of diagnosis. The present study aimed to compare the accuracy of two different set of primers targeting the small subunit ribosomal RNA (ssRNA) and the dihydrofolate reductase-thymidylate synthase linker region (dhfr-ts) in detecting species specific malaria infections by nested PCR. The sensitivity and specificity of nested PCR assay using the two primers were calculated with reference to microscopy as the 'gold standard'. The results show that 18S rRNA primers had 91.9% sensitivity and 100% specificity in detecting human Plasmodium species as opposed to dhfr-ts primers which had 51.4% sensitivity and 100% specificity. The higher sensitivity of 18S rRNA primers suggests that it may be a better diagnostic tool for detecting human malaria.
    Matched MeSH terms: DNA Primers/genetics; DNA, Intergenic
  13. Ma XR, Edmund Sim UH, Pauline B, Patricia L, Rahman J
    Trop Biomed, 2008 Apr;25(1):46-57.
    PMID: 18600204 MyJurnal
    Colorectal carcinoma (CRC) arises as a result of mutational activation of oncogenes coupled with inactivation of tumour suppressor genes. Mutations in APC, K-ras and p53 have been commonly reported. In a previous study by our group, the tumour susceptibility gene 101 (TSG101) were found to be persistently upregulated in CRC cases. TSG101 was reported to be closely related to cancers of the breast, brain and colon, and its overexpression in human papillary thyroid carcinomas and ovarian carcinomas had previously been reported. The wingless-type MMTV integration site family member 2 (WNT2) is potentially important in the Wnt/beta-catenin pathway and upregulation of WNT2 is not uncommon in human cancers. In this study, we report the investigation for mutation(s) and expression pattern(s) of WNT2 and TSG101, in an effort to further understand their role(s) in CRC tumourigenesis. Our results revealed no mutation in these genes, despite their persistent upregulation in CRC cases studied.
    Matched MeSH terms: DNA-Binding Proteins/genetics*; DNA-Binding Proteins/metabolism
  14. Dinesh B, Furusawa G, Amirul AA
    Arch Microbiol, 2017 Jan;199(1):63-67.
    PMID: 27506901 DOI: 10.1007/s00203-016-1275-8
    A Gram-staining-negative, aerobic, rod-shaped, yellow-orange-pigmented, gliding bacterium, designated as strain ST2L12(T), was isolated from estuarine mangrove sediment from Matang Mangrove Forest, Perak, Malaysia. Strain ST2L12(T) grew at 15-39 °C, pH 6-8 and in 1-6 % (w/v) NaCl. This strain was able to degrade xylan and casein. 16S rRNA gene sequence analysis showed 95.3-92.8 % similarity to members of the genera Mangrovimonas, Meridianimaribacter, Sediminibacter, Gaetbulibacter and Hoppeia. Phylogenetic analysis indicated that it belonged to the family Flavobacteriaceae. Respiratory quinone present was menaquinone-6 (MK-6), and the DNA G+C content was 38.3 mol%. The predominant fatty acids were iso-C15:0, iso-C15:1, C15:0 and iso-C17:0 3-OH. Moreover, previous genome comparison study showed that the genome of ST2L12(T) is 1.4 times larger compared to its closest relative, Mangrovimonas yunxiaonensis LYYY01(T). Phenotypic, fatty acid, 16S rRNA gene sequence and previous genome data indicate that strain ST2L12(T) represents a novel species of the genus Mangrovimonas in the family Flavobacteriaceae, for which the name Mangrovimonas xylaniphaga sp. nov. is proposed. The type strain of Mangrovimonas xylaniphaga is ST2L12(T) (=LMG 28914(T)=JCM 30880(T)).
    Matched MeSH terms: DNA, Bacterial/genetics; Sequence Analysis, DNA
  15. Uni S, Mat Udin AS, Agatsuma T, Saijuntha W, Junker K, Ramli R, et al.
    Parasit Vectors, 2017 Apr 20;10(1):194.
    PMID: 28427478 DOI: 10.1186/s13071-017-2105-9
    BACKGROUND: The filarial nematodes Wuchereria bancrofti (Cobbold, 1877), Brugia malayi (Brug, 1927) and B. timori Partono, Purnomo, Dennis, Atmosoedjono, Oemijati & Cross, 1977 cause lymphatic diseases in humans in the tropics, while B. pahangi (Buckley & Edeson, 1956) infects carnivores and causes zoonotic diseases in humans in Malaysia. Wuchereria bancrofti, W. kalimantani Palmieri, Pulnomo, Dennis & Marwoto, 1980 and six out of ten Brugia spp. have been described from Australia, Southeast Asia, Sri Lanka and India. However, the origin and evolution of the species in the Wuchereria-Brugia clade remain unclear. While investigating the diversity of filarial parasites in Malaysia, we discovered an undescribed species in the common treeshrew Tupaia glis Diard & Duvaucel (Mammalia: Scandentia).

    METHODS: We examined 81 common treeshrews from 14 areas in nine states and the Federal Territory of Peninsular Malaysia for filarial parasites. Once any filariae that were found had been isolated, we examined their morphological characteristics and determined the partial sequences of their mitochondrial cytochrome c oxidase subunit 1 (cox1) and 12S rRNA genes. Polymerase chain reaction (PCR) products of the internal transcribed spacer 1 (ITS1) region were then cloned into the pGEM-T vector, and the recombinant plasmids were used as templates for sequencing.

    RESULTS: Malayfilaria sofiani Uni, Mat Udin & Takaoka, n. g., n. sp. is described based on the morphological characteristics of adults and microfilariae found in common treeshrews from Jeram Pasu, Kelantan, Malaysia. The Kimura 2-parameter distance between the cox1 gene sequences of the new species and W. bancrofti was 11.8%. Based on the three gene sequences, the new species forms a monophyletic clade with W. bancrofti and Brugia spp. The adult parasites were found in tissues surrounding the lymph nodes of the neck of common treeshrews.

    CONCLUSIONS: The newly described species appears most closely related to Wuchereria spp. and Brugia spp., but differs from these in several morphological characteristics. Molecular analyses based on the cox1 and 12S rRNA genes and the ITS1 region indicated that this species differs from both W. bancrofti and Brugia spp. at the genus level. We thus propose a new genus, Malayfilaria, along with the new species M. sofiani.

    Matched MeSH terms: Sequence Analysis, DNA; DNA, Ribosomal Spacer/genetics
  16. Kwong WK, Moran NA
    Int J Syst Evol Microbiol, 2016 Mar;66(3):1323-1329.
    PMID: 26743158 DOI: 10.1099/ijsem.0.000882
    Honey bees and bumble bees harbour a small, defined set of gut bacterial associates. Strains matching sequences from 16S rRNA gene surveys of bee gut microbiotas were isolated from two honey bee species from East Asia. These isolates were mesophlic, non-pigmented, catalase-positive and oxidase-negative. The major fatty acids were iso-C15 : 0, iso-C17 : 0 3-OH, C16 : 0 and C16 : 0 3-OH. The DNA G+C content was 29-31 mol%. They had ∼87 % 16S rRNA gene sequence identity to the closest relatives described. Phylogenetic reconstruction using 20 protein-coding genes showed that these bee-derived strains formed a highly supported monophyletic clade, sister to the clade containing species of the genera Chryseobacterium and Elizabethkingia within the family Flavobacteriaceae of the phylum Bacteroidetes. On the basis of phenotypic and genotypic characteristics, we propose placing these strains in a novel genus and species: Apibacter adventoris gen. nov., sp. nov. The type strain of Apibacter adventoris is wkB301T ( = NRRL B-65307T = NCIMB 14986T).
    Matched MeSH terms: DNA, Bacterial/genetics; Sequence Analysis, DNA
  17. Wilson JJ, Brandon-Mong GJ, Gan HM, Sing KW
    PMID: 29591722 DOI: 10.1080/24701394.2018.1455189
    Consensus on the optimal high-throughput sequencing (HTS) approach to examine biodiversity in mixed terrestrial arthropod samples has not been reached. Metatranscriptomics could increase the proportion of taxonomically informative mitochondrial reads in HTS outputs but has not been investigated for terrestrial arthropod samples. We compared the efficiency of 16S rRNA metabarcoding, metagenomics and metatranscriptomics for detecting species in a mixed terrestrial arthropod sample (pooled DNA/RNA from 38 taxa). 16S rRNA metabarcoding and nuclear rRNA-depleted metatranscriptomics had the highest detection rate with 97% of input species detected. Based on cytochrome c oxidase I, metagenomics had the highest detection rate with 82% of input species detected, but metatranscriptomics produced a larger proportion of reads matching (Sanger) reference sequences. Metatranscriptomics with nuclear rRNA depletion may offer advantages over metabarcoding through reducing the number of spurious operational taxonomic units while retaining high detection rates, and offers natural enrichment of mitochondrial sequences which may enable increased species detection rates compared with metagenomics.
    Matched MeSH terms: DNA Barcoding, Taxonomic/methods*; DNA Barcoding, Taxonomic/standards
  18. Chewapreecha C, Holden MT, Vehkala M, Välimäki N, Yang Z, Harris SR, et al.
    Nat Microbiol, 2017 Jan 23;2:16263.
    PMID: 28112723 DOI: 10.1038/nmicrobiol.2016.263
    The environmental bacterium Burkholderia pseudomallei causes an estimated 165,000 cases of human melioidosis per year worldwide and is also classified as a biothreat agent. We used whole genome sequences of 469 B. pseudomallei isolates from 30 countries collected over 79 years to explore its geographic transmission. Our data point to Australia as an early reservoir, with transmission to Southeast Asia followed by onward transmission to South Asia and East Asia. Repeated reintroductions were observed within the Malay Peninsula and between countries bordered by the Mekong River. Our data support an African origin of the Central and South American isolates with introduction of B. pseudomallei into the Americas between 1650 and 1850, providing a temporal link with the slave trade. We also identified geographically distinct genes/variants in Australasian or Southeast Asian isolates alone, with virulence-associated genes being among those over-represented. This provides a potential explanation for clinical manifestations of melioidosis that are geographically restricted.
    Matched MeSH terms: DNA, Bacterial/genetics; Sequence Analysis, DNA
  19. Li Y, Huang CX, Xu GS, Lundholm N, Teng ST, Wu H, et al.
    Harmful Algae, 2017 07;67:119-130.
    PMID: 28755714 DOI: 10.1016/j.hal.2017.06.008
    The genus Pseudo-nitzschia has attracted attention because of production of the toxin, domoic acid (DA), causing Amnesic Shellfish Poisoning (ASP). Pseudo-nitzschia blooms occur frequently in Chinese coastal waters, and DA has been detected in several marine organisms, but so far no Pseudo-nitzschia strains from Chinese waters have been shown to produce DA. In this study, monoclonal Pseudo-nitzschia strains were established from Chinese coastal waters and examined using light microscopy, electron microscopy and molecular markers. Five strains, sharing distinct morphological and molecular features differentiating them from other Pseudo-nitzschia species, represent a new species, Pseudo-nitzschia simulans sp. nov. Morphologically, the taxon belongs to the P. pseudodelicatissima group, cells possessing a central nodule and each stria comprising one row of poroids. The new species is characterized by the poroid structure, which typically comprises two sectors, each sector located near opposite margins of the poroid. The production of DA was examined by liquid chromatography tandem mass spectrometry (LC-MS/MS) analyses of cells in stationary growth phase. Domoic acid was detected in one of the five strains, with concentrations around 1.05-1.54 fg cell-1. This is the first toxigenic diatom species reported from Chinese waters.
    Matched MeSH terms: DNA, Ribosomal Spacer/genetics; DNA, Ribosomal Spacer/chemistry
  20. King JL, Churchill JD, Novroski NMM, Zeng X, Warshauer DH, Seah LH, et al.
    Forensic Sci Int Genet, 2018 09;36:60-76.
    PMID: 29935396 DOI: 10.1016/j.fsigen.2018.06.005
    The use of single nucleotide polymorphisms (SNPs) in forensic genetics has been limited to challenged samples with low template and/or degraded DNA. The recent introduction of massively parallel sequencing (MPS) technologies has expanded the potential applications of these markers and increased the discrimination power of well-established loci by considering variation in the flanking regions of target loci. The ForenSeq Signature Preparation Kit contains 165 SNP amplicons for ancestry- (aiSNPs), identity- (iiSNPs), and phenotype-inference (piSNPs). In this study, 714 individuals from four major populations (African American, AFA; East Asian, ASN; US Caucasian, CAU; and Southwest US Hispanic, HIS) previously reported by Churchill et al. [Forensic Sci Int Genet. 30 (2017) 81-92; DOI: https://doi.org/10.1016/j.fsigen.2017.06.004] were assessed using STRait Razor v2s to determine the level of diversity in the flanking regions of these amplicons. The results show that nearly 70% of loci showed some level of flanking region variation with 22 iiSNPs and 8 aiSNPs categorized as microhaplotypes in this study. The heterozygosities of these microhaplotypes approached, and in one instance surpassed, those of some core STR loci. Also, the impact of the flanking region on other forensic parameters (e.g., power of exclusion and power of discrimination) was examined. Sixteen of the 94 iiSNPs had an effective allele number greater than 2.00 across the four populations. To assess what effect the flanking region information had on the ancestry inference, genotype probabilities and likelihood ratios were determined. Additionally, concordance with the ForenSeq UAS and Nextera Rapid Capture was evaluated, and patterns of heterozygote imbalance were identified. Pairwise comparison of the iiSNP diplotypes determined the probability of detecting a mixture (i.e., observing ≥ 3 haplotypes) using these loci alone was 0.9952. The improvement in random match probabilities for the full regions over the target iiSNPs was found to be significant. When combining the iiSNPs with the autosomal STRs, the combined match probabilities ranged from 6.40 × 10-73 (ASN) to 1.02 × 10-79 (AFA).
    Matched MeSH terms: DNA Fingerprinting; Sequence Analysis, DNA*
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