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Search Results: 1 - 8 of 8 matches for " Naowarat Cheeptham "
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A Review of Scientific Teaching
Naowarat Ann Cheeptham
Journal of Microbiology & Biology Education , 2011, DOI: 10.1128/jmbe.v12i1.287
Abstract: N/A
Investigating the Effects of Hydrophobicity and Charge on the Therapeutic Ability of the Antimicrobial Histatin 8 Peptide for Potential Use in Oral Applications
Scott M. G. Matheson,Naowarat Cheeptham,Heidi E. K. Huttunen-Hennelly
International Journal of Biology , 2013, DOI: 10.5539/ijb.v5n2p85
Abstract: Advances in technology allow for the construction of synthetic antibiotics, which includes the development of de novo antimicrobial peptides (AMPs). The contents of AMPs including amino acids, chain length, hydrophobicity, ring structure/rigidity, terminus and charge when modified can alter the antimicrobial properties. A special family of peptides called histatins is naturally excreted by oral glands as an immune response, and previous research shows their potential for treating thrush. Histatin 8 is known to have antimicrobial activity against yeast strains and the goal of this study was to synthesize histatin 8 and two novel derivatives (delt 1 and delt 4) that fall at extremes of each other with regard to charge and hydrophobicity in order to investigate the properties that could optimize antimicrobial properties. The derivatives were characterized using various chemical and biological assays to investigate the effects of charge and hydrophobicity on bioactivity. Compared to histatin 8, delt 4’s minimum inhibitory concentration (MIC) was decreased more than tenfold against Candida tropicalis indicating increased antimicrobial activity. Re-inoculation confirmed fungicidal properties.
Cure from the cave: volcanic cave actinomycetes and their potential in drug discovery
Cheeptham N.,Sadoway T.,Rule D.,Watson K.
International Journal of Speleology , 2013,
Abstract: Volcanic caves have been little studied for their potential as sources of novel microbial species and bioactive compounds with new scaffolds. We present the f irst study of volcanic cave microbiology from Canada and suggest that this habitat has great potential for the isolation of novel bioactive substances. Sample locat ions were plot ted on a contour map that was compiled in ArcView 3.2. Over 400 bacterial isolates were obtained from the Helmcken Falls cave in Wells Gray Provincial Park, British Columbia. From our preliminary screen, of 400 isolates tested, 1% showed activity against extended spectrum -lactamase E. coli, 1.75% against Escherichia coli, 2.25% against Acinetobacter baumannii, and 26.50% against Klebsiella pneumoniae. In addition, 10.25% showed activity against Micrococcus luteus, 2% against methicillin resistant Staphylococcus aureus, 9.25% against Mycobacterium smegmatis, 6.25% Pseudomonas aeruginosa and 7.5% against Candida albicans. Chemical and physical characteristics of three rock wall samples were studied using scanning electron microscopy and f lame atomic absorption spectrometry. Calcium (Ca), iron (Fe), and aluminum (Al) were the most abundant components while magnesium (Mg), sodium (Na), arsenic (As), lead (Pb), chromium (Cr), and barium (Ba) were second most abundant with cadmium (Cd) and potassium (K) were the least abundant in our samples. Scanning electron microscopy (SEM) showed the presence of microscopic life forms in all three rock wall samples. 16S rRNA gene sequencing of 82 isolates revealed that 65 (79.3%) of the strains belong to the Streptomyces genus and 5 (6.1%) were members of Bacillus, Pseudomonas, Nocardia and Erwinia genera. Interestingly, twelve (14.6%) of the 16S rRNA sequences showed similarity to unidentif ied ribosomal RNA sequences in the library databases, the sequences of these isolates need to be further investigated using the EzTaxon-e database (http://eztaxon-e. ezbiocloud.net/) to determine whether or not these are novel species. Nevertheless, this suggests the possibility that they could be unstudied or rare bacteria. The Helmcken Falls cave microbiome possesses a great diversity of microbes with the potential for studies of novel microbial interactions and the isolation of new types of antimicrobial agents.
Molecular diagnosis of eosinophilic meningitis due to Angiostrongylus cantonensis (Nematoda: Metastrongyloidea) by polymerase chain reaction-DNA sequencing of cerebrospinal fluids of patients
Eamsobhana, Praphathip;Wanachiwanawin, Darawan;Dechkum, Naowarat;Parsartvit, Anchana;Yong, Hoi Sen;
Memórias do Instituto Oswaldo Cruz , 2013, DOI: 10.1590/S0074-02762013000100020
Abstract: cerebrospinal fluid (csf) samples from clinically diagnosed patients with detectable angiostrongylus canto-nensis-specific antibodies (n = 10), patients with clinically suspected cases that tested negative for a. cantonensis-an-tibodies (n = 5) and patients with cerebral gnathostomiasis (n = 2) and neurocysticercosis (n = 2) were examined by a single-step polymerase chain reaction (pcr) method using the ac primers for the 66-kda native protein gene. the pcr method detected a. cantonensis dna in csf samples from four of 10 serologically confirmed angiostrongyliasis cases. the pcr results were negative for the remaining csf samples. the nucleotide sequences of three positive csf-pcr samples shared 98.8-99.2% similarity with the reference sequence of a. cantonensis. these results indicate the potential application of this pcr assay with clinical csf samples for additional support in the confirmation of eosinophilic meningitis due to a. cantonensis.
Genetic diversity and population structure of Plasmodium falciparum in Thailand, a low transmission country
Tepanata Pumpaibool, Céline Arnathau, Patrick Durand, Naowarat Kanchanakhan, Napaporn Siripoon, Aree Suegorn, Chitr Sitthi-amorn, Fran?ois Renaud, Pongchai Harnyuttanakorn
Malaria Journal , 2009, DOI: 10.1186/1475-2875-8-155
Abstract: The diversity and genetic differentiation of P. falciparum populations were analysed using 12 polymorphic apparently neutral microsatellite loci distributed on eight of the 14 different chromosomes. Samples were collected from seven provinces in the western, eastern and southern parts of Thailand.A strong difference in the nuclear genetic structure was observed between most of the assayed populations. The genetic diversity was comparable to the intermediate level observed in low P. falciparum transmission areas (average HS = 0.65 ± 0.17), where the lowest is observed in South America and the highest in Africa. However, uniquely the Yala province, had only a single multilocus genotype present in all samples, leading to a strong geographic differentiation when compared to the other Thai populations during this study. Comparison of the genetic structure of P. falciparum populations in Thailand with those in the French Guyana, Congo and Cameroon revealed a significant genetic differentiation between all of them, except the two African countries, whilst the genetic variability of P. falciparum amongst countries showed overlapping distributions.Plasmodium falciparum shows genetically structured populations across local areas of Thailand. Although Thailand is considered to be a low transmission area, a relatively high level of genetic diversity and no linkage disequilibrium was found in five of the studied areas, the exception being the Yala province (Southern peninsular Thailand), where a clonal population structure was revealed and in Kanchanaburi province (Western Thailand). This finding is particularly relevant in the context of malaria control, because it could help in understanding the special dynamics of parasite populations in areas with different histories of, and exposure to, drug regimens.Malaria is still one of the most important infectious diseases, endemic in the tropical and sub-tropical parts of about 102 countries, especially in the African continent. In T
Genetic diversity of Plasmodium vivax in Kolkata, India
Jung-Ryong Kim, Mallika Imwong, Amitabha Nandy, Kesinee Chotivanich, Apichart Nontprasert, Naowarat Tonomsing, Ardhendu Maji, Manjulika Addy, Nick PJ Day, Nicholas J White, Sasithon Pukrittayakamee
Malaria Journal , 2006, DOI: 10.1186/1475-2875-5-71
Abstract: Blood from 151 patients with P. vivax infection diagnosed in Kolkata between April 2003 and September 2004 was genotyped at three polymorphic loci: the P. vivax circumsporozoite protein (pvcs), the merozoite surface protein 1 (pvmsp1) and the merozoite surface protein 3-alpha (pvmsp3-alpha).Analysis of these three genetic markers revealed that P. vivax populations in Kolkata are highly diverse. A large number of distinguishable alleles were found from three genetic markers: 11 for pvcs, 35 for pvmsp1 and 37 for pvmsp3-alpha. These were, in general, randomly distributed amongst the isolates. Among the 151 isolates, 142 unique genotypes were detected the commonest genotype at a frequency of less than 2% (3/151). The overall rate of mixed genotype infections was 10.6%.These results indicate that the P. vivax parasite population is highly diverse in Kolkata, despite the low level of transmission. The genotyping protocols used in this study may be useful for differentiating re-infection from relapse and recrudescence in studies assessing of malarial drug efficacy in vivax malaria.Malaria remains one of the most important communicable diseases in the world. Despite enormous control efforts over many decades malaria is still a significant health problem. It is estimated that around 300–500 million cases occur each year with one to three million deaths. The problem is compounded by multiple drug resistance in Plasmodium falciparum and chloroquine resistance in Plasmodium vivax [1]. The global burden of malaria due to P. vivax is 70–80 million cases annually. Vivax malaria is usually a non-lethal infection but its prolonged and recurrent infection can have major deleterious effects on personal well-being, growth and on the economic performance at the individual, family, community and national levels [2]. The recent emergence of chloroquine-resistant strains is of great concern [3-5].P. vivax causes about 60–65% of all malaria infections in India [6,7,42]. The frequency of re
Genetic Variability of Plasmodium malariae dihydropteroate synthase (dhps) in Four Asian Countries
Naowarat Tanomsing, Mayfong Mayxay, Paul N. Newton, Francois Nosten, Christiane Dolecek, Tran Tinh Hien, Nicholas J. White, Nicholas P. J. Day, Arjen M. Dondorp, Mallika Imwong
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0093942
Abstract: The dihydropteroate synthase (dhps) genes of 44 P. malariae strains from four Asian countries were isolated. Only a limited number of polymorphisms were observed. Comparison with homologous mutations in other Plasmodium species showed that these polymorphisms are unlikely to be associated with sulfadoxine resistance.
A Population Survey of the Glucose-6-Phosphate Dehydrogenase (G6PD) 563C>T (Mediterranean) Mutation in Afghanistan
Natsuda Jamornthanyawat, Ghulam R. Awab, Naowarat Tanomsing, Sasithon Pukrittayakamee, Fazel Yamin, Arjen M. Dondorp, Nicholas P. J. Day, Nicholas J. White, Charles J. Woodrow, Mallika Imwong
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0088605
Abstract: Glucose-6-phosphate dehydrogenase (G6PD) deficiency is a common inherited enzyme defect and an important problem in areas with Plasmodium vivax infection because of the risk of haemolysis following administration of primaquine to treat the liver forms of the parasite. We undertook a genotypic survey of 713 male individuals across nine provinces of Afghanistan in which malaria is found, four in the north and five in the east. RFLP typing at nucleotide position 563 detected 40 individuals with the Mediterranean mutation 563C>T, an overall prevalence of 5.6%. This varied according to self-reported ethnicity, with prevalence in the Pashtun/Pashai group of 33/369 (8.9%) compared to 7/344 individuals in the rest of the population (2.0%; p<0.001, Chi-squared test). Multivariate analysis of ethnicity and geographical location indicated an adjusted odds ratio of 3.50 (95% CI 1.36–9.02) for the Pashtun/Pashai group, while location showed only a trend towards higher prevalence in eastern provinces (adjusted odds ratio = 1.73, 0.73–4.13). Testing of known polymorphic markers (1311C>T in exon 11, and C93T in intron XI) in a subset of 82 individuals wild-type at C563 revealed a mixture of 3 haplotypes in the background population and was consistent with data from the 1000 Genomes Project and published studies. By comparison individuals with G6PD deficiency showed a highly skewed haplotype distribution, with 95% showing the CT haplotype, a finding consistent with relatively recent appearance and positive selection of the Mediterranean variant in Afghanistan. Overall, the data confirm that the Mediterranean variant of G6PD is common in many ethnic groups in Afghanistan, indicating that screening for G6PD deficiency is required in all individuals before radical treatment of P. vivax with primaquine.
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