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  1. Ramelah M, Aminuddin A, Alfizah H, Isa MR, Jasmi AY, Tan HJ, et al.
    FEMS Immunol. Med. Microbiol., 2005 May 1;44(2):239-42.
    PMID: 15866222
    Helicobacter pylori infection of a distinct subtype of cagA may lead to different pathological manifestation. The aim of this study is to determine the presence of cagA gene and its variants in H. pylori infection among different ethnic groups and its effect on gastroduodenal diseases. Overall detection of cagA among the 205 clinical isolates of H. pylori was 94%. Variations in size of the 3' region of cagA gene were examined among 192 Malaysian H. pylori cagA-positive strains. Results showed that three cagA variants differing in fragment length of PCR products were detected and designated as type A (621-651bp), type B (732-735bp) and type C (525 bp). Although there was no association between any of the cagA subtypes with peptic ulcer disease (p>0.05), an association between cagA subtypes with a specific ethnic group was observed. Specific-cagA subtype A strains were predominantly isolated from Chinese compared to Malays and Indians (p<0.0005), and cagA subtype B strains were predominantly isolated from Malays and Indians compared to Chinese (p<0.05). The cagA type A strains of H. pylori is commonly found in the Chinese patients who have a higher risk of peptic ulcer disease, thus indicating that it could be used as an important clinical biomarker for a more severe infection.
    Matched MeSH terms: Genetic Variation*
  2. Lie-Injo LE, Ganesan J, Herrera A, Lopez CG
    Hum. Hered., 1978;28(1):37-40.
    PMID: 304028
    In a study of Malaysians of different racial groups, 1,510 sera (908 from Malays, 371 from Chinese and 231 from Indians) were identified for their protease inhibitor (Pi) types. The gene frequencies for the alleles PiM, PiS and PiX in Malays were, respectively, 0.979, 0.015, and 0.007. In Chinese, the frequencies were 0.981, 0.019 and 0.000, and in Indians they were 0.976, 0.24, and 0.000. It is interesting that the usually rare PiX type is found in appreciable frequency in the Malays. Two different types with unusual behavior and obscure origin were also found.
    Matched MeSH terms: Genetic Variation*
  3. Hu FJ, Li YD, Jiao SL, Zhang S
    Zhonghua Yu Fang Yi Xue Za Zhi, 2013 Dec;47(12):1100-4.
    PMID: 24529267
    To investigate the epidemiological characteristics of influenza B viruses and explore the genetic evolution characteristics of the hemagglutinin(HA) and neuraminidase(NA) genes of local isolated strains in Ningbo, Southeast China, during 2010 to 2012.
    Matched MeSH terms: Genetic Variation
  4. Mattick J, Libro S, Bromley R, Chaicumpa W, Chung M, Cook D, et al.
    PLoS Negl Trop Dis, 2021 Oct;15(10):e0009838.
    PMID: 34705823 DOI: 10.1371/journal.pntd.0009838
    The sequence diversity of natural and laboratory populations of Brugia pahangi and Brugia malayi was assessed with Illumina resequencing followed by mapping in order to identify single nucleotide variants and insertions/deletions. In natural and laboratory Brugia populations, there is a lack of sequence diversity on chromosome X relative to the autosomes (πX/πA = 0.2), which is lower than the expected (πX/πA = 0.75). A reduction in diversity is also observed in other filarial nematodes with neo-X chromosome fusions in the genera Onchocerca and Wuchereria, but not those without neo-X chromosome fusions in the genera Loa and Dirofilaria. In the species with neo-X chromosome fusions, chromosome X is abnormally large, containing a third of the genetic material such that a sizable portion of the genome is lacking sequence diversity. Such profound differences in genetic diversity can be consequential, having been associated with drug resistance and adaptability, with the potential to affect filarial eradication.
    Matched MeSH terms: Genetic Variation*
  5. Ahmed MA, Chu KB, Vythilingam I, Quan FS
    Malar J, 2018 Nov 29;17(1):442.
    PMID: 30497496 DOI: 10.1186/s12936-018-2583-z
    BACKGROUND: The C-terminal 42 kDa domain of Plasmodium knowlesi merozoite surface protein 1 (PkMSP1) is a potential asexual blood-stage vaccine candidate, however, only a limited number of clinical isolates have been analysed from Malaysia and no inter-country comparative diversity study has been conducted. In the present study, nucleotide diversity, haplotypes and natural selection levels of pkmsp1 in clinical samples from geographically distinct regions of Malaysia and Thailand were investigated. The overall population structure of the parasite from the region was determined.

    METHODS: Eleven full-length pkmsp1 sequences obtained from clinical isolates of Malaysia along with the H-strain were downloaded from the database for domain wise characterization of pkmsp1 gene. Additionally, 76 pkmsp-142 sequences from Thailand and Malaysia were downloaded from the database for intra and inter-population analysis. DnaSP 5.10 and MEGA 5.0 software were used to determine genetic diversity, polymorphism, haplotypes and natural selection. Genealogical relationships were determined using haplotype network tree in NETWORK software v5.0. Population genetic differentiation index (FST) of parasites were analysed using Arlequin v3.5.

    RESULTS: Sequence analysis of 11 full-length pkmsp1 sequences along with the H-strain identified 477 (8.4%) polymorphic sites, of which 107 were singleton sites. The overall diversity observed in the full-length genes were high in comparison to its ortholog pvmsp1 and the 4 variable domains showed extensive size variations. The nucleotide diversity was low towards the pkmsp1-42 compared to the conserved domains. The 19 kDa domain was less diverse and completely conserved among isolates from Malaysian Borneo. The nucleotide diversity of isolates from Peninsular Malaysia and Thailand were higher than Malaysian Borneo. Network analysis of pkmsp1-42 haplotypes showed geographical clustering of the isolates from Malaysian Borneo and grouping of isolates from Peninsular Malaysia and Thailand. Population differentiation analysis indicated high FST values between parasite populations originating from Malaysian Borneo, Peninsular Malaysia and Thailand attributing to geographical distance. Moderate genetic differentiation was observed for parasite populations from Thailand and Peninsular Malaysia. Evidence of population expansion and purifying selection were observed in all conserved domains with strongest selection within the pkmsp1-42 domain.

    CONCLUSIONS: This study is the first to report on inter country genetic diversity and population structure of P. knowlesi based on msp1. Strong evidence of negative selection was observed in the 42 kDa domain, indicating functional constrains. Geographical clustering of P. knowlesi and moderate to high genetic differentiation values between populations identified in this study highlights the importance of further evaluation using larger number of clinical samples from Southeast Asian countries.

    Matched MeSH terms: Genetic Variation*
  6. Benjamin G
    Hum Biol, 2013 Feb-Jun;85(1-3):445-84.
    PMID: 24297237
    The primary focus of this article is on the so-called negritos of Peninsular Malaysia and southern Thailand, but attention is also paid to other parts of Southeast Asia. I present a survey of current views on the "negrito" phenotype--is it single or many? If the phenotype is many (as now seems likely), it must have resulted from parallel evolution in the several different regions where it has been claimed to exist. This would suggest (contrary to certain views that have been expressed on the basis of very partial genetic data) that the phenotype originated recently and by biologically well-authenticated processes from within the neighboring populations. Whole-genome and physical-anthropological research currently support this view. Regardless of whether the negrito phenotype is ancient or recent-and to the extent that it retains any valid biological reality (which is worth questioning)-explanations are still needed for its continued distinctiveness. In the Malay Peninsula, a distinctive "Semang" societal pattern followed by most, but not all, so-called negritos may have been responsible for this by shaping familial, breeding, and demographic patterns to suit the two main modes of environmental appropriation that they have followed, probably for some millennia: nomadic foraging in the forest, and facultative dependence on exchange or labor relations with neighboring populations. The known distribution of "negritos" in the Malay Peninsula is limited to areas within relatively easy reach of archaeologically authenticated premodern transpeninsular trading and portage routes, as well as of other non-negrito, Aslian-speaking populations engaged in swidden farming. This suggests that their continued distinctiveness has resulted from a wish to maintain a complementary advantage vis-à-vis other, less specialized populations. Nevertheless, a significant degree of discordance exists between the associated linguistic, societal-tradition, and biological patterns which suggests that other factors have also been at play.
    Matched MeSH terms: Genetic Variation
  7. Gan HM, Eng WWH, Barton MK, Adams LE, Samsudin NA, Bartl AJ, et al.
    Genome Announc, 2017 Aug 24;5(34).
    PMID: 28839032 DOI: 10.1128/genomeA.00857-17
    We report here the genome sequences of Salmonella enterica subsp. enterica serovar Typhimurium strains TT6675 and TT9097, which we utilize for genetic analyses of giant bacterial viruses. Our analyses identified several genetic variations between the two strains, most significantly confirming strain TT6675 as a serine suppressor and TT9097 as a nonsuppressor.
    Matched MeSH terms: Genetic Variation
  8. Benavente ED, Gomes AR, De Silva JR, Grigg M, Walker H, Barber BE, et al.
    Sci Rep, 2019 07 08;9(1):9873.
    PMID: 31285495 DOI: 10.1038/s41598-019-46398-z
    The zoonotic Plasmodium knowlesi parasite is the most common cause of human malaria in Malaysia. Genetic analysis has shown that the parasites are divided into three subpopulations according to their geographic origin (Peninsular or Borneo) and, in Borneo, their macaque host (Macaca fascicularis or M. nemestrina). Whilst evidence suggests that genetic exchange events have occurred between the two Borneo subpopulations, the picture is unclear in less studied Peninsular strains. One difficulty is that P. knowlesi infected individuals tend to present with low parasitaemia leading to samples with insufficient DNA for whole genome sequencing. Here, using a parasite selective whole genome amplification approach on unprocessed blood samples, we were able to analyse recent genomes sourced from both Peninsular Malaysia and Borneo. The analysis provides evidence that recombination events are present in the Peninsular Malaysia parasite subpopulation, which have acquired fragments of the M. nemestrina associated subpopulation genotype, including the DBPβ and NBPXa erythrocyte invasion genes. The NBPXb invasion gene has also been exchanged within the macaque host-associated subpopulations of Malaysian Borneo. Our work provides strong evidence that exchange events are far more ubiquitous than expected and should be taken into consideration when studying the highly complex P. knowlesi population structure.
    Matched MeSH terms: Genetic Variation/genetics*
  9. Gan HM, Gan HY, Ahmad NH, Aziz NA, Hudson AO, Savka MA
    PMID: 25621282 DOI: 10.3389/fcimb.2014.00188
    Here we report the draft genomes and annotation of four N-acyl homoserine lactone (AHL)-producing members from the family Sphingomonadaceae. Comparative genomic analyses of 62 Sphingomonadaceae genomes were performed to gain insights into the distribution of the canonical luxI/R-type quorum sensing (QS) network within this family. Forty genomes contained at least one luxR homolog while the genome of Sphingobium yanoikuyae B1 contained seven Open Reading Frames (ORFs) that have significant homology to that of luxR. Thirty-three genomes contained at least one luxI homolog while the genomes of Sphingobium sp. SYK6, Sphingobium japonicum, and Sphingobium lactosutens contained four luxI. Using phylogenetic analysis, the sphingomonad LuxR homologs formed five distinct clades with two minor clades located near the plant associated bacteria (PAB) LuxR solo clade. This work for the first time shows that 13 Sphingobium and one Sphingomonas genome(s) contain three convergently oriented genes composed of two tandem luxR genes proximal to one luxI (luxR-luxR-luxI). Interestingly, luxI solos were identified in two Sphingobium species and may represent species that contribute to AHL-based QS system by contributing AHL molecules but are unable to perceive AHLs as signals. This work provides the most comprehensive description of the luxI/R circuitry and genome-based taxonomical description of the available sphingomonad genomes to date indicating that the presence of luxR solos and luxI solos are not an uncommon feature in members of the Sphingomonadaceae family.
    Matched MeSH terms: Genetic Variation*
  10. Foong CP, Lau NS, Deguchi S, Toyofuku T, Taylor TD, Sudesh K, et al.
    BMC Microbiol, 2014;14:318.
    PMID: 25539583 DOI: 10.1186/s12866-014-0318-z
    Special features of the Japanese ocean include its ranges of latitude and depth. This study is the first to examine the diversity of Class I and II PHA synthases (PhaC) in DNA samples from pelagic seawater taken from the Japan Trench and Nankai Trough from a range of depths from 24 m to 5373 m. PhaC is the key enzyme in microorganisms that determines the types of monomer units that are polymerized into polyhydroxyalkanoate (PHA) and thus affects the physicochemical properties of this thermoplastic polymer. Complete putative PhaC sequences were determined via genome walking, and the activities of newly discovered PhaCs were evaluated in a heterologous host.
    Matched MeSH terms: Genetic Variation
  11. Tajima S, Nakayama E, Kotaki A, Moi ML, Ikeda M, Yagasaki K, et al.
    Jpn J Infect Dis, 2017 Jan 24;70(1):45-49.
    PMID: 27169954 DOI: 10.7883/yoken.JJID.2016.086
    Cases of autochthonous infections of dengue virus type 1 (DENV-1) were detected in Japan after a 70-year period devoid of dengue outbreaks. We previously showed that E gene sequences are identical in 11 of the 12 DENV-1 strains autochthonous to Japan. However, the E sequence represents only 14% of the DENV-1 genome. In the present study, we have sequenced the entire genome of 6 autochthonous DENV-1 strains that were isolated from patients during the 2014 outbreak. Sequencing of 5 Yoyogi group strains with identical E sequences and 1 Shizuoka strain with a different E sequence revealed that the first Yoyogi group strain differed from the Shizuoka strain by 18 amino acid residues. Furthermore, 2 Yoyogi group strains had different genomic sequences while the other 3 had identical genomes. Phylogenetic analyses indicated that the Hyogo strain, a Yoyogi group strain, was the first to diverge from the other 4 Yoyogi group strains. The E gene sequence of the Yoyogi group strains exhibits the highest homology to those of the strains isolated in Malaysia and Singapore between 2013 and 2014. The patient infected with the Hyogo strain visited Malaysia before the onset of dengue fever, suggesting that this was a case of dengue infection imported from Malaysia.
    Matched MeSH terms: Genetic Variation*
  12. Neik TX, Chai JY, Tan SY, Sudo MPS, Cui Y, Jayaraj J, et al.
    G3 (Bethesda), 2019 09 04;9(9):2941-2950.
    PMID: 31292156 DOI: 10.1534/g3.119.400021
    Weedy crop relatives are among the world's most problematic agricultural weeds, and their ability to rapidly evolve can be enhanced by gene flow from both domesticated crop varieties and wild crop progenitor species. In this study, we examined the role of modern commercial crop cultivars, traditional landraces, and wild relatives in the recent emergence and proliferation of weedy rice in East Malaysia on the island of Borneo. This region of Malaysia is separated from the Asian continent by the South China Sea, and weedy rice has become a major problem there more recently than on the Malaysian peninsular mainland. Using 24 polymorphic SSR loci and genotype data from the awn-length domestication gene An-1, we assessed the genetic diversity, population structure and potential origins of East Malaysian weeds; 564 weedy, cultivated and wild rice accessions were analyzed from samples collected in East Malaysia, Peninsular Malaysia and neighboring countries. While there is considerable evidence for contributions of Peninsular Malaysian weed ecotypes to East Malaysian populations, we find that local crop cultivars and/or landraces from neighboring countries are also likely contributors to the weedy rice infestations. These findings highlight the implications of genetic admixture from different cultivar source populations in the spread of weedy crop relatives and the urgent need for preventive measurements to maintain sustainable crop yields.
    Matched MeSH terms: Genetic Variation*
  13. Ng KT, Oong XY, Lim SH, Chook JB, Takebe Y, Chan YF, et al.
    Clin Infect Dis, 2018 07 02;67(2):261-268.
    PMID: 29385423 DOI: 10.1093/cid/ciy063
    Background: Rhinovirus (RV) is one of the main viral etiologic agents of acute respiratory illnesses. Despite the heightened disease burden caused by RV, the viral factors that increase the severity of RV infection, the transmission pattern, and seasonality of RV infections remain unclear.

    Methods: An observational study was conducted among 3935 patients presenting with acute upper respiratory illnesses in the ambulatory settings between 2012 and 2014.

    Results: The VP4/VP2 gene was genotyped from all 976 RV-positive specimens, where the predominance of RV-A (49%) was observed, followed by RV-C (38%) and RV-B (13%). A significant regression in median nasopharyngeal viral load (VL) (P < .001) was observed, from 883 viral copies/µL at 1-2 days after symptom onset to 312 viral copies/µL at 3-4 days and 158 viral copies/µL at 5-7 days, before declining to 35 viral copies/µL at ≥8 days. In comparison with RV-A (median VL, 217 copies/µL) and RV-B (median VL, 275 copies/µL), RV-C-infected subjects produced higher VL (505 copies/µL; P < .001). Importantly, higher RV VL (median, 348 copies/µL) was associated with more severe respiratory symptoms (Total Symptom Severity Score ≥17, P = .017). A total of 83 phylogenetic-based transmission clusters were identified in the population. It was observed that the relative humidity was the strongest environmental predictor of RV seasonality in the tropical climate.

    Conclusions: Our findings underline the role of VL in increasing disease severity attributed to RV-C infection, and unravel the factors that fuel the population transmission dynamics of RV.

    Matched MeSH terms: Genetic Variation
  14. Adler PH, Takaoka H, Sofian-Azirun M, Low VL, Ya'cob Z, Chen CD, et al.
    PLoS One, 2016;11(10):e0163881.
    PMID: 27695048 DOI: 10.1371/journal.pone.0163881
    The increasing attention on Vietnam as a biodiversity hotspot prompted an investigation of the potential for cryptic diversity in black flies, a group well known elsewhere for its high frequency of isomorphic species. We analyzed the banding structure of the larval polytene chromosomes in the Simulium tuberosum species group to probe for diversity beyond the morphological level. Among 272 larvae, 88 different chromosomal rearrangements, primarily paracentric inversions, were discovered in addition to 25 already known in the basic sequences of the group in Asia. Chromosomal diversity in Vietnam far exceeds that known for the group in Thailand, with only about 5% of the rearrangements shared between the two countries. Fifteen cytoforms and nine morphoforms were revealed among six nominal species in Vietnam. Chromosomal evidence, combined with available molecular and morphological evidence, conservatively suggests that at least five of the cytoforms are valid species, two of which require formal names. The total chromosomal rearrangements and species (15) now known from the group in Vietnam far exceed those of any other area of comparable size in the world, supporting the country's status as a biodiversity hotspot. Phylogenetic inference based on uniquely shared, derived chromosomal rearrangements supports the clustering of cytoforms into two primary lineages, the Simulium tani complex and the Southeast Asian Simulium tuberosum subgroup. Some of these taxa could be threatened by habitat destruction, given their restricted geographical distributions and the expanding human population of Vietnam.
    Matched MeSH terms: Genetic Variation*
  15. Ishar SM, Parameswaran K, Masduki NS, Rus Din RD
    PMID: 31709874 DOI: 10.1080/24701394.2019.1687693
    DNA variations are alterations found in DNA sequence, occurring in both nuclear DNA and mitochondrial DNA. Variations might differ in individual following population, respectively. The aim of this study was to find variations in target sequence of mtDNA (16000-16200) to be used as marker in Malay and Chinese population. A total of 30 buccal swab samples from 20 Malay and 10 Chinese subjects were collected and preserved on FTA card. The FTA card that contained DNA sample was punched to be included into polymerase chain reaction mixture. Amplification was carried out and the products were sequenced. Sequence variations were found in both Malay and Chinese populations. A total of nine variations (16129, 16108, 16162, 16172, 16148, 16127, 16173, 16099 and 16100) were found in Malay population while a total of seven variations (16129, 16104, 16111, 16109, 16164, 16170 and 16136) were found in Chinese population. Nucleotide position 16129 was found as variation in both Malay and Chinese populations. This study implies that np 16129 can be used as a marker for Malaysian population. For further investigation, the length of the target sequence may be increased to obtain more variations that can be used as markers. This will increase the discrimination power of Malaysian population.
    Matched MeSH terms: Genetic Variation/genetics*
  16. Rao ES, Kadirvel P, Symonds RC, Geethanjali S, Thontadarya RN, Ebert AW
    PLoS One, 2015;10(7):e0132535.
    PMID: 26161546 DOI: 10.1371/journal.pone.0132535
    Association analysis was conducted in a core collection of 94 genotypes of Solanum pimpinellifolium to identify variations linked to salt tolerance traits (physiological and yield traits under salt stress) in four candidate genes viz., DREB1A, VP1.1, NHX1, and TIP. The candidate gene analysis covered a concatenated length of 4594 bp per individual and identified five SNP/Indels in DREB1A and VP1.1 genes explaining 17.0% to 25.8% phenotypic variation for various salt tolerance traits. Out of these five alleles, one at 297 bp in DREB1A had in-frame deletion of 6 bp (CTGCAT) or 12 bp (CTGCATCTGCAT), resulting in two alleles, viz., SpDREB1A_297_6 and SpDREB1A_297_12. These alleles individually or as haplotypes accounted for maximum phenotypic variance of about 25% for various salt tolerance traits. Design of markers for selection of the favorable alleles/haplotypes will hasten marker-assisted introgression of salt tolerance from S. pimpinellifolium into cultivated tomato.
    Matched MeSH terms: Genetic Variation
  17. Ganesan J, Lie-Injo LE, Ong Beng P
    Hum. Hered., 1976;26(2):124-7.
    PMID: 181317
    The Land and Sea Dayaks of Sarawak were surveyed for several erythrocyte enzymes. The gene frequency of 6PGDC in 132 Land Dayaks and 127 Sea Dayaks were 0.045 and 0.047, respectively. The gene frequency of PGM1-1 IN 285 Land Dayks and 240 Sea Dayaks were 0.716 and 0.779, respectively. The ADA2 gene frequency in 283 Land Dayaks and 188 Sea Dayaks were 0.154 and 0.090. ADA 5-1 was found once in the Land Dayaks and once in the Sea Dayaks. AK 2-1 was found once in 221 Sea Dayaks but not in any of 270 Land Dayaks. No PHI, LDH or CA variants were found among the Land or Sea Dayaks.
    Matched MeSH terms: Genetic Variation
  18. Yosida TH, Sagai T
    Chromosoma, 1975;50(3):283-300.
    PMID: 1149576
    All subspecies of black rats (Rattus rattus) used in the present study are characterized by having large and clear C-bands at the centromeric region. The appearance of the bands, however, is different in the subspecies. Chromosome pair No. 1 in Asian type black rats (2n=42), which are characterized by an acrocentric and subtelocentric polymorphism, showed C-band polymorphism. In Phillipine rats (R. rattus mindanensis) the pair was subtelocentric with C-bands, but in Malayan black rats (R. rattus diardii) it was usually acrocentric with C-bands. In Hong-Kong (R. rattus flavipectus) and Japanese black rats (R. rattus tanezumi) it was polymorphic with respect to the presence of acrocentrics with C-bands or subtelocentrics without C-bands. The other chromosomes pairs showed clear C-bands, but in Hong-Kong black rats the pairs No. 2 and 5 were polymorphic with and without C-bands. In Japanese black rats, 6 chromosome pairs (No. 3, 4, 7, 9, 11 and 13) were polymorphic in regard to presence and absence of C-bands, but the other 5 chromosome pairs (No. 2, 5, 6, 8 and 10) showed always absence of C-bands. Only pair No. 12 usually showed C-bands. C-bands in small metacentric pairs (No. 14 to 20) in Asian type black rats generally large in size, but those in the Oceanian (2n=38) and Ceylon type black rats (2n=40) were small. In the hybrids between Asian and Oceanian type rats, heteromorphic C-bands, one large and the other small, were observed. Based on the consideration of karyotype evolution in the black rats, the C-band is suggested to have a tendency toward the diminution as far as the related species are concerned.
    Matched MeSH terms: Genetic Variation*
  19. Freeman MA, Ogawa K
    Int J Parasitol, 2010 Feb;40(2):255-64.
    PMID: 19715695 DOI: 10.1016/j.ijpara.2009.08.006
    Numerous global reports of the species Udonella caligorum, currently thought to be a species complex, suggests that the group may be species-rich. Herein we describe Udonella fugu n. sp., previously described as U. caligorum, found on the parasitic copepod Pseudocaligus fugu infecting Takifugu spp. from Japan. Using morphological data U. fugu can be distinguished from the current valid species by at least one of the traditionally used characters in udonellid taxonomy, and phylogenetic analyses of ssrDNA sequence data for U. fugu and other udonellids confirm that U. fugu forms a distinct clade from other udonellids including U. caligorum. Variable regions in the ssrDNA demonstrated a range of between 2.75 and 5.5% difference between currently recognized species of Udonella. These differences in ssrDNA sequences are phylogenetically useful when distinguishing between morphologically similar udonellids and can be used in conjunction with other data (morphology, phylogeography and fish host) to help clarify udonellid systematics. Udonella fugu was also found to cause significant damage to farmed tiger puffers through their feeding activities. Individual skin lesions were round in shape but merged with adjoining lesions to form more extensive lacerations. In some of the specimens from P. fugu infecting Takifugu niphobles, the protozoan ciliate Trichodina was found on the udonellid body surface and in their intestinal contents. We conclude that the udonellids are a more species-rich group than currently recognized, that early descriptions of new species may have been synonymized with U. caligorum in error and that the frequent global reports of U. caligorum may actually represent new species. This has led to a wide range of morphological descriptions for U. caligorum, blurring the usefulness of morphological data for the group.
    Matched MeSH terms: Genetic Variation*
  20. Seethamchai S, Buppan P, Kuamsab N, Teeranaipong P, Putaporntip C, Jongwutiwes S
    Infect Genet Evol, 2018 11;65:35-42.
    PMID: 30016713 DOI: 10.1016/j.meegid.2018.07.015
    The amino acid substitution at residue 76 of the food vacuolar transmembrane protein encoded by the chloroquine resistance transporter gene of Plasmodium falciparum (Pfcrt) is an important, albeit imperfect, determinant of chloroquine susceptibility status of the parasite. Other mutations in Pfcrt can modulate susceptibility of P. falciparum to other antimalarials capable of interfering with heme detoxification process, and may exert compensatory effect on parasite growth rate. To address whether nationwide implementation of artemisinin combination therapy (ACT) in Thailand could affect sequence variation in exon 2 and introns of Pfcrt, we analyzed 136 P. falciparum isolates collected during 1997 and 2016 from endemic areas bordering Myanmar, Cambodia and Malaysia. Results revealed 6 haplotypes in exon 2 of Pfcrt with 2 novel substitutions at c.243A > G (p.R81) and c.251A > T (p.N84I). Positive selection was observed at amino acid residues 75, 76 and 97. Four, 3, and 2 alleles of microsatellite (AT/TA) repeats occurred in introns 1, 2 and 4, respectively, resulting in 7 different 3-locus haplotypes. The number of haplotypes and haplotype diversity of exon 2, and introns 1, 2 and 4 were significantly greater among isolates collected during 2009 and 2016 than those collected during 1997 and 2008 when 3-day ACT and 2-day ACT regimens were implemented nationwide, respectively (p 
    Matched MeSH terms: Genetic Variation
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