Displaying publications 41 - 60 of 735 in total

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  1. The genetic characteristics and evolution of Tembusu virus
    Lei W, Guo X, Fu S, Feng Y, Tao X, Gao X, et al.
    Vet Microbiol, 2017 Mar;201:32-41.
    PMID: 28284620 DOI: 10.1016/j.vetmic.2017.01.003
    BACKGROUND: Since the turn of the 21st century, there have been several epidemic outbreaks of poultry diseases caused by Tembusu virus (TMUV). Although multiple mosquito and poultry-derived strains of TMUV have been isolated, no data exist about their comparative study, origin, evolution, and dissemination.

    METHODOLOGY: Parallel virology was used to investigate the phenotypes of duck and mosquito-derived isolates of TMUV. Molecular biology and bioinformatics methods were employed to investigate the genetic characteristics and evolution of TMUV.

    PRINCIPAL FINDINGS: The plaque diameter of duck-derived isolates of TMUV was larger than that of mosquito-derived isolates. The cytopathic effect (CPE) in mammalian cells occurred more rapidly induced by duck-derived isolates than by mosquito-derived isolates. Furthermore, duck-derived isolates required less time to reach maximum titer, and exhibited higher viral titer. These findings suggested that poultry-derived TMUV isolates were more invasive and had greater expansion capability than the mosquito-derived isolates in mammalian cells. Variations in amino acid loci in TMUV E gene sequence revealed two mutated amino acid loci in strains isolated from Malaysia, Thailand, and Chinese mainland compared with the prototypical strain of the virus (MM1775). Furthermore, TMUV isolates from the Chinese mainland had six common variations in the E gene loci that differed from the Southeast Asian strains. Phylogenetic analysis indicated that TMUV did not exhibit a species barrier in avian species and consisted of two lineages: the Southeast Asian and the Chinese mainland lineages. Molecular traceability studies revealed that the recent common evolutionary ancestor of TMUV might have appeared before 1934 and that Malaysia, Thailand and Shandong Province of China represent the three main sources related to TMUV spread.

    CONCLUSIONS: The current broad distribution of TMUV strains in Southeast Asia and Chinese mainland exhibited longer-range diffusion and larger-scale propagation. Therefore, in addition to China, other Asian and European countries linked to Asia have used improved measures to detect and monitor TMUV related diseases to prevent epidemics in poultry.

    Matched MeSH terms: Genetic Variation*
  2. Genetic diversity of bluetongue viruses in Australasia
    Pritchard LI, Daniels PW, Melville LF, Kirkland PD, Johnson SJ, Lunt R, et al.
    Vet. Ital., 2004 Oct-Dec;40(4):438-45.
    PMID: 20422566
    The authors have characterised the genetic diversity of the bluetongue virus (BTV) RNA segments 3 and 10 from Indonesia, Malaysia and Australia. Analysis of RNA segment 3, which codes for the core protein VP3, showed conserved sequences in the previously defined Australasian topotype, but which further divided into four distinct clades or genotypes. Certain genotypes appeared to be geographically restricted while others were distributed widely throughout South-East Asia. Ongoing surveillance programmes in Australia have identified the movement of Indonesian genotypes into northern Australia and possible reassortment among them. Similarly, analysis of RNA segment 10, which codes for the non-structural protein NS3/3A, showed they were also conserved and grouped into five clades or genotypes, three Asian and two North American/South African.
    Matched MeSH terms: Genetic Variation
  3. Fulltext Genetic diversity of Japanese encephalitis virus isolates obtained from the Indonesian archipelago between 1974 and 1987
    Schuh AJ, Guzman H, Tesh RB, Barrett AD
    Vector Borne Zoonotic Dis, 2013 Jul;13(7):479-88.
    PMID: 23590316 DOI: 10.1089/vbz.2011.0870
    Five genotypes (GI-V) of Japanese encephalitis virus (JEV) have been identified, all of which have distinct geographical distributions and epidemiologies. It is thought that JEV originated in the Indonesia-Malaysia region from an ancestral virus. From that ancestral virus GV diverged, followed by GIV, GIII, GII, and GI. Genotype IV appears to be confined to the Indonesia-Malaysia region, as GIV has been isolated in Indonesia from mosquitoes only, while GV has been isolated on three occasions only from a human in Malaysia and mosquitoes in China and South Korea. In contrast, GI-III viruses have been isolated throughout Asia and Australasia from a variety of hosts. Prior to this study only 13 JEV isolates collected from the Indonesian archipelago had been studied genetically. Therefore the sequences of the envelope (E) gene of 24 additional Indonesian JEV isolates, collected throughout the archipelago between 1974 and 1987, were determined and a series of molecular adaptation analyses were performed. Phylogenetic analysis indicated that over a 14-year time span three genotypes of JEV circulated throughout Indonesia, and a statistically significant association between the year of virus collection and genotype was revealed: isolates collected between 1974 and 1980 belonged to GII, isolates collected between 1980 and 1981 belonged to GIV, and isolates collected in 1987 belonged to GIII. Interestingly, three of the GII Indonesian isolates grouped with an isolate that was collected during the JE outbreak that occurred in Australia in 1995, two of the GIII Indonesian isolates were closely related to a Japanese isolate collected 40 years previously, and two Javanese GIV isolates possessed six amino acid substitutions within the E protein when compared to a previously sequenced GIV isolate collected in Flores. Several amino acids within the E protein of the Indonesian isolates were found to be under directional evolution and/or co-evolution. Conceivably, the tropical climate of the Indonesia/Malaysia region, together with its plethora of distinct fauna and flora, may have driven the emergence and evolution of JEV. This is consistent with the extensive genetic diversity seen among the JEV isolates observed in this study, and further substantiates the hypothesis that JEV originated in the Indonesia-Malaysia region.
    Matched MeSH terms: Genetic Variation*
  4. Genetic and immunologic relationships between vaccine and field strains for vaccine selection of type A foot-and-mouth disease virus circulating in East Asia
    Lee SY, Park ME, Kim RH, Ko MK, Lee KN, Kim SM, et al.
    Vaccine, 2015 Jan 29;33(5):664-9.
    PMID: 25528521 DOI: 10.1016/j.vaccine.2014.12.007
    Of the seven known serotypes of foot-and-mouth disease virus (FMDV), type A has the most diverse variations. Genetic variations also occur frequently at VP1, VP2, VP3, and VP4 because these proteins constitute the viral capsid. The structural proteins of FMDV, which are closely related to immunologic correlations, are the most easily analyzed because they have highly accessible information. In this study we analyzed the type A vaccine viruses by alignment of available sequences in order to find appropriate vaccine strains. The matching rate of ASIA topotype-specific sites (20 amino acids) located on the viral surface, which are mainly VP1 and VP2, was highly related to immunologic reactivity. Among the available vaccines analyzed in this study, we suggest that A Malaysia 97 could be used as a vaccine virus as it has the highest genetic similarity and immunologic aspects to field strains originating in East Asia.
    Matched MeSH terms: Genetic Variation*
  5. POPULATION GENETICS OF LONGTAIL TUNA (Thunnus tonggol) (BLEEKER, 1851) FROM EAST MALAYSIA BASED ON MITOCHONDRIAL DNA D-LOOP MARKER
    NURUL AZLIANA MOHD YASIN, NOORHANI SYAHIDA KASIM, TUN NURUL AIMI MAT JAAFAR, RUMEAIDA MAT PIAH, WAHIDAH MOHD ARSHAAD, SITI AZIZAH MOHD NOR, et al.
    UMT Journal of Undergraduate Research, 2020;2(2):49-56.
    MyJurnal
    Present study investigates the genetic diversity and genetic distribution of the longtail tuna Thunnus tonggol collected from east Malaysia (Borneo states of Sabah and Sarawak) based on mitochondrial DNA D-loop sequence analysis. 58 fish samples were obtained, specifically from Kota Kinabalu, KK (n = 22), Miri, MR (n=20) and Bintulu, BT (n = 17). DNA template was isolated using the salt extraction method. Final length of 404 base pair (bp) D-loop sequences revealed 52 haplotypes that comprise of 77 variable sites (38 of parsimony informative and 39 singleton). A total of 20 haplotypes were found in KK, 19 haplotypes in MR and 16 haplotypes in BT. Molecular diversity indices revealed high haplotype diversity and low nucleotide diversity in all populations; KK (h = 0.9913 ± 0.0165, π = 0.00239 ± 0.0127), MR (h = 0.9942 ± 0.0193, π = 0.0226 ± 0.0121) and BT (h = 0.9926 ± 0.0230, π = 0.0196 ± 0.0171). Population comparison pairwise FST show that KK and BT were significantly genetically differentiated. The result from this study will be beneficial for fisheries management and also to provide information on the population genetics of T. tonggol in East Malaysian waters.
    Matched MeSH terms: Genetic Variation
  6. Fulltext Phylogenetic Relatedness of Several Agarwood-Producing Taxa (Thymelaeaceae) from Indonesia
    Lee SY, Turjaman M, Mohamed R
    Trop Life Sci Res, 2018 Jul;29(2):13-28.
    PMID: 30112138 MyJurnal DOI: 10.21315/tlsr2018.29.2.2
    Indonesia is home to several tree taxa that are harvested for agarwood. This highly valuable oleoresin ironically was the cause for some species to become vulnerable due to gluttonous human activity. However, information on the genetic diversity of these endangered trees is limited. In this study, 28 specimens representing eight species from two genera, Aquilaria and Gyrinops, were collected from ex-situ and in-situ populations in Indonesia. Phylogenetic analysis conducted on DNA sequences of the nuclear ribosomal internal transcribed spacer (ITS) and the trnL-trnF intergenic spacer regions, revealed that Aquilaria and Gyrinops are paraphyletic when Aquilaria cumingiana is excluded. The phylogenetic analysis for ITS and trnL-trnF showed capability to categorise agarwood-producing species based on their regions: East Indonesia and West Indonesia, using Wallace's Line as the divider. In addition, we discuss challenges in species identification and taxonomy of agarwood-producing genera, and their conservation efforts in Indonesia.
    Matched MeSH terms: Genetic Variation
  7. Fulltext Detection and characterization of viruses causing hand, foot and mouth disease from children in Seri Kembangan, Malaysia
    Ling BP, Jalilian FA, Harmal NS, Yubbu P, Sekawi Z
    Trop Biomed, 2014 Dec;31(4):654-62.
    PMID: 25776590 MyJurnal
    Hand, foot and mouth disease (HFMD) is a common viral infection among infants and children. The major causative agents of HFMD are enterovirus 71 (EV71) and coxsackievirus A16 (CVA16). Recently, coxsackievirus A6 (CVA6) infections were reported in neighboring countries. Infected infants and children may present with fever, mouth/throat ulcers, rashes and vesicles on hands and feet. Moreover, EV71 infections might cause fatal neurological complications. Since 1997, EV71 caused fatalities in Sarawak and Peninsula Malaysia. The purpose of this study was to identify and classify the viruses which detected from the patients who presenting clinical signs and symptoms of HFMD in Seri Kembangan, Malaysia. From December 2012 until July 2013, a total of 28 specimens were collected from patients with clinical case definitions of HFMD. The HFMD viruses were detected by using semi-nested reverse transcription polymerase chain reaction (snRT-PCR). The positive snRT-PCR products were sequenced and phylogenetic analyses of the viruses were performed. 12 of 28 specimens (42.9%) were positive in snRT-PCR, seven are CVA6 (58.3%), two CVA16 (16.7%) and three EV71 (25%). Based on phylogenetic analysis studies, EV71 strains were identified as sub-genotype B5; CVA16 strains classified into sub-genotype B2b and B2c; CVA6 strains closely related to strains in Taiwan and Japan. In this study, HFMD in Seri Kembangan were caused by different types of Enterovirus, which were EV71, CVA6 and CVA16.
    Matched MeSH terms: Genetic Variation*
  8. Fulltext Investigation of toxin genes among methicillin-resistant Staphylococcus aureus strains isolated from a tertiary hospital in Malaysia
    Lim KT, Hanifah YA, Mohd Yusof MY, Thong KL
    Trop Biomed, 2012 Jun;29(2):212-9.
    PMID: 22735842 MyJurnal
    Staphylococcus aureus is a persistent human pathogen responsible for a variety of infections ranging from soft-tissue infections to bacteremia. It produces a variety of virulence factors which are responsible for specific acute staphylococcal toxaemia syndromes. The objective of this study was to determine the prevalence of a repertoire of toxin genes among Malaysian MRSA strains and their genetic diversity by PCR-RFLP of coa gene. One hundred eighty-eight strains (2003, 2004, 2007 and 2008) of methicillin-resistant S. aureus (MRSA) were screened for 20 genes encoding for extracellular virulence determinant (sea, seb, sec, sed, see, seg, seh, sei, sej, tst, eta, etb, etd) and adhesins (cna, etb, fnbA, fnbB, hlg, ica, sdrE). The genetic relatedness of these strains was determined by PCR-RFLP of coa gene and agr grouping. Majority of the strains were tested positive for efb and fnbA (96% each), ica (78%) and hlg (59%) genes. A total of 101 strains were positive for at least one type of staphylococcal enterotoxin genes with sea being the predominant. Genes for seb, sed, see, seh, sej, eta and etb were not detected in any of the MRSA strains. The prevalence of sea, sec and ica among strains isolated in 2008 was increased significantly (p< 0.05) compared to 2003. Most of the strains were of agr type I (97.5%) followed by agr type II (1.2%) and agr type III (0.6%). All sea, sei and tst gene-positive strains were of agr type I. The only etd positive strain was agr type III. PCR-RFLP of coa produced 47 different patterns. The number of strains with virulence factors (sea, sec and ica) had increased over the years. No direct correlation between PCR-RFLP- coa profiles and virulotypes was observed.
    Matched MeSH terms: Genetic Variation
  9. Fulltext Comparative genetic analysis of VP4, VP1 and 3D gene regions of enterovirus 71 and coxsackievirus A16 circulating in Malaysia between 1997-2008
    Chan YF, Wee KL, Chiam CW, Khor CS, Chan SY, Amalina W MZ, et al.
    Trop Biomed, 2012 Sep;29(3):451-66.
    PMID: 23018509 MyJurnal
    Three genomic regions, VP4 capsid, VP1 capsid and 3D RNA polymerase of human enterovirus 71 (EV-71) and coxsackievirus A16 (CV-A16) were sequenced to understand the evolution of these viruses in Malaysia. A total of 42 EV-71 and 36 CV-A16 isolates from 1997- 2008 were sequenced. Despite the presence of many EV-71 subgenotypes worldwide, only subgenotypes B3, B4, B5, C1 and C2 were present in Malaysia. Importation of other subgenotypes such as C3, C4/D and C5 from other countries was infrequent. For CV-A16, the earlier subgenotype B1 was replaced by subgenotypes B2a and the recent B2c. Subgenotype B2a was present throughout the study while B2c only emerged in 2005. No genetic signatures could be attributed to viral virulence suggesting that host factors have a major role in determining the outcome of infection. Only three EV-71 B3 isolates showed non-consistent phylogeny in the 3D RNA polymerase region which indicated occurrence of recombination in EV-71. High genetic diversity was observed in the Malaysian EV-71 but Malaysian CV-A16 showed low genetic diversity in the three genomic regions sequenced. EV-71 showed strong purifying selection, but that occurred to a lesser extent in CV-A16.
    Matched MeSH terms: Genetic Variation*
  10. Fulltext Sequence variation in the cytochrome oxidase subunit I and II genes of two commonly found blow fly species, Chrysomya megacephala (Fabricius) and Chrysomya rufifacies (Macquart) (Diptera: Calliphoridae) in Malaysia
    Tan SH, Aris EM, Surin J, Omar B, Kurahashi H, Mohamed Z
    Trop Biomed, 2009 Aug;26(2):173-81.
    PMID: 19901904
    The mitochondiral DNA region encompassing the cytochrome oxidase subunit I (COI) and cytochrome oxidase subunit II (COII) genes of two Malaysian blow fly species, Chrysomya megacephala (Fabricius) and Chrysomya rufifacies (Macquart) were studied. This region, which spans 2303bp and includes the COI, tRNA leucine and partial COII was sequenced from adult fly and larval specimens, and compared. Intraspecific variations were observed at 0.26% for Ch. megacephala and 0.17% for Ch. rufifacies, while sequence divergence between the two species was recorded at a minimum of 141 out of 2303 sites (6.12%). Results obtained in this study are comparable to published data, and thus support the use of DNA sequence to facilitate and complement morphology-based species identification.
    Matched MeSH terms: Genetic Variation*
  11. Fulltext Characterization of vancomycin-resistant Enterococcus isolates from broilers in Selangor, Malaysia
    Getachew YM, Hassan L, Zakaria Z, Saleha AA, Kamaruddin MI, Che Zalina MZ
    Trop Biomed, 2009 Dec;26(3):280-8.
    PMID: 20237442 MyJurnal
    Vancomycin-resistant Enterococcus (VRE) is an emerging nosocomial pathogen in humans. The use of antibiotics in human therapy and in the production of food animals has been incriminated in the emergence of this organism. The present study describes the distribution of VRE species, the vancomycin-resistant genes detected, the vancomycin resistance pattern observed, and the genetic diversity of the isolates found in live broiler chickens in Malaysia. Overall 140 VRE were isolated with species comprising Enterococcus faecalis (48%), Enterococcus faecium (25.7%), Enterococcus gallinarum (12.1%), Enterococcus casseliflavus (1.4%) and other Enterococcus species (12.8%). Vancomycin resistance gene vanA and intrinsic genes vanC1 and vanC2/3 were detected in the study population. VanA was detected in 15 (63.9%) of E. faecium, 23 (22.4%) of E. faecalis and in 3 (17.6%) E. gallinarum isolates. E-test was conducted on randomly selected 41 of the isolates and the minimum inhibition concentration (MIC) of vancomycin for five (11.9%) of tested isolates is more than 256 μg/ml. Genotypic analysis using random amplified polymorphic DNA (RAPD) showed genetic diversity within the Enterococcus species.
    Matched MeSH terms: Genetic Variation
  12. Molecular diagnosis and genetic diversity of Cryptosporidium spp. in exotic birds of southwest of Iran
    Jalas M, Tavalla M
    Trop Biomed, 2018 Dec 01;35(4):944-950.
    PMID: 33601843
    Cryptosporidium parasites can infect a wide range of vertebrate hosts including reptiles, mammals, and birds. Due to the zoonotic nature of cryptosporidiosis and its close contact with exotic birds and humans, the present study aimed to determine the prevalence and genetic diversity of Cryptosporidium spp. in exotic birds of southwest of Iran, by the staining and molecular methods. In the present research, 369 stool specimens were randomly collected from exotic birds and stained by modified acid-fast stain using Ziehl-Neelsen method. The slides were examined using light microscopy at a magnification of 100X. Then, the extracted DNA was amplified using the PCR method. Finally, all genotypes and positive samples from PCR assay were sequenced by Bioneer Company (Daejeon, South Korea). Among 369 stool specimens, 25 and 27 cases were found to be positive for Cryptosporidium spp. by the modified Ziehl-Neelsen staining and the PCR methods, respectively. Based on the genotyping, C. avian genotype III and C. meleagridis were detected in 25 and 2 stool samples, respectively. The results revealed a relatively high prevalence of Cryptosporidium spp. in exotic birds in the southwest of Iran. Due to the zoonotic nature of C. meleagridis, these exotic birds can be a significant source of cryptosporidiosis. It is important that high-risk people, including immune-deficient patients, receive correct information about the risk of indirect and direct contact with infected exotic birds.
    Matched MeSH terms: Genetic Variation
  13. Genetic diversity, antifungal susceptibility and enzymatic characterisation of Malaysian clinical isolates of Candida glabrata
    Lotfalikhani A, Khosravi Y, Sabet NS, Na SL, Ng KP, Tay ST
    Trop Biomed, 2018 Dec 01;35(4):1123-1130.
    PMID: 33601859
    Candida glabrata has been reported as the second or third most common yeast species isolated from patients with vaginitis and invasive candidiasis. This study was aimed to determine the genetic diversity, antifungal susceptibility and enzymatic profiles of C. glabrata isolated from vaginal and blood samples in the Medical Microbiology Diagnostic Laboratory, University Malaya Medical Centre. A random amplified polymorphic DNA (RAPD) analysis method, using M13 and (GTG)5 primers, was used for strain differentiation of C. glabrata isolates. Antifungal susceptibility testing of C. glabrata isolates was determined using E-test against amphotericin B, caspofungin, fluconazole and voriconazole and microbroth dilution method against clotrimazole. The enzymic profiles of C. glabrata were determined using APIZYM semi-quantitation kit and egg-yolk agar method. A total of 14 RAPD patterns were identified amongst C. glabrata isolates investigated this study. Susceptibility to amphotericin B, caspofungin, fluconazole and voriconazole was noted. Approximately one third of the isolates demonstrated resistance to clotrimazole (MIC>=1 µg/ml). A single isolate of C. glabrata was resistant to caspofungin (MIC:1.5 µg/ml). Enzymatic activities of acid and alkaline phosphatase, aminopeptidases, esterase and lipase and phospholipase were detected in the C. glabrata isolates. The genetic diversity and antifungal susceptibility profiles of C. glabrata isolates were presented in this study. Continued surveillance and monitoring of the incidence and antifungal resistance in C. glabrata isolates is necessary.
    Matched MeSH terms: Genetic Variation
  14. Genetic diversity and DNA barcoding of the black fly (Diptera: Simuliidae) vectors of parasites causing human onchocerciasis in Guatemala
    Pramual P, Bunchom N, Saijuntha W, Tada I, Suganuma N, Agatsuma T
    Trop Biomed, 2019 Dec 01;36(4):938-957.
    PMID: 33597465
    Genetic variation based on mitochondrial cytochrome c oxidase I (COI) and II (COII) sequences was investigated for three black fly nominal species, Simulium metallicum Bellardi complex, S. callidum Dyar and Shannon, and S. ochraceum Walker complex, which are vectors of human onchocerciasis from Guatemala. High levels of genetic diversity were found in S. metallicum complex and S. ochraceum complex with maximum intraspecific genetic divergences of 11.39% and 4.25%, respectively. Levels of genetic diversity of these nominal species are consistent with species status for both of them as they are cytologically complexes of species. Phylogenetic analyses revealed that the S. metallicum complex from Guatemala divided into three distinct clades, two with members of this species from several Central and South American countries and another exclusively from Mexico. The Simulium ochraceum complex from Guatemala formed a clade with members of this species from Mexico and Costa Rica while those from Ecuador and Colombia formed another distinct clade. Very low diversity in S. callidum was found for both genes with maximum intraspecific genetic divergence of 0.68% for COI and 0.88% for COII. Low genetic diversity in S. callidum might be a consequence of the result being informative of only recent population history of the species.
    Matched MeSH terms: Genetic Variation*
  15. Global genetic diversity of Spirometra tapeworms
    Hong X, Liu SN, Xu FF, Han LL, Jiang P, Wang ZQ, et al.
    Trop Biomed, 2020 Mar 01;37(1):237-250.
    PMID: 33612735
    Spirometra larvae are etiological agents of human sparganosis. However, the systematics of spirometrid cestodes has long been controversial. In order to determine the current knowledge on the evolution and genetic structure of Spirometra, an exhaustive population diversity analysis of spirometrid cestodes using the mitochondrial gene: cytochrome c oxidase subunit 1 (cox1) was performed. All publicly available cox1 sequences available in the GenBank and 127 new sequencing genes from China were used as the dataset. The haplotype identify, network, genetic differentiation and phylogenetic analysis were conducted successively. A total of 488 sequences from 20 host species, representing four spirometrid tapeworms (S. decipiens, S. ranarum, S. erinaceieuropaei and Sparganum proliferum) and several unclassified American and African isolates from 113 geographical locations in 17 countries, identified 45 haplotypes. The genetic analysis revealed that there are four clades of spirometrid cestodes: Clade 1 (Brazil + USA) and Clade 2 (Argentina + Venezuela) included isolates from America, Clade 3 contained African isolates and one Korean sample, and the remainders from Asia and Australia belonged to Clade 4; unclassified Spirometra from America and Africa should be considered the separate species within the genus; and the taxonomy of two Korea isolates (S. erinaceieuropaei KJ599680 and S. decipiens KJ599679) was still ambiguous and needs to be further identified. In addition, the demographical analyses supported population expansion for the total spirometrid population. In summary, four lineages were found in the spirometrid tapeworm, and further investigation with deeper sampling is needed to elucidate the population structure.
    Matched MeSH terms: Genetic Variation*
  16. Genetic variation of NADH dehydrogenase subunit 1 (nad1) mitochondrial gene sequence in adult Necator americanus hookworms recovered from a female patient in Thailand
    Eamsobhana P, Yong HS, Roongruangchai K, Tungtrongchitr A, Wanachiwanawin D
    Trop Biomed, 2020 Jun 01;37(2):536-541.
    PMID: 33612820
    Two female and one male adult hookworms were recovered from a female patient in Thailand. Based on gross and microscopic morphology, the three hookworms are members of Necator americanus. Phylogenetic reconstruction based on partial NADH dehydrogenase subunit 1 (nad1) mitochondrial gene sequences shows that these hookworms belong to the same genetic lineage as N. americanus adult worm from Zhejiang, China. The male and female hookworms were genetically distinct, belonging to two different nad1-haplotypes. This is the first report targeting the nad1 gene on the identification and genetic characterization of the human hookworms originated from infected patient. The nad1 gene marker is useful for species and higher taxa differentiation of hookworms.
    Matched MeSH terms: Genetic Variation*
  17. Genetic diversity of the full length apical membrane antigen-1 of Plasmodium knowlesi clinical isolates from Peninsular Malaysia
    Ng YL, Fong MY, Lau YL
    Trop Biomed, 2021 Jun 01;38(2):159-164.
    PMID: 34172705 DOI: 10.47665/tb.38.2.052
    The Plasmodium knowlesi apical membrane antigen-1 (PkAMA-1) plays an important role in the invasion of the parasite into its host erythrocyte, and it has been regarded as a potential vaccine candidate against human knowlesi malaria. This study investigates genetic diversity and natural selection of the full length PkAMA-1 of P. knowlesi clinical isolates from Peninsular Malaysia. Blood samples were collected from P. knowlesi malaria patients from Peninsular Malaysia. The PkAMA-1 gene was amplified from DNA samples using PCR, cloned into a plasmid vector and sequenced. Results showed that nucleotide diversity of the full length PkAMA-1 from Peninsular Malaysia isolates (π: 0.006) was almost similar to that of Sarawak (π: 0.005) and Sabah (π: 0.004) isolates reported in other studies. Deeper analysis revealed Domain I (π: 0.007) in the PkAMA-1 had the highest diversity as compared to Domain II (π: 0.004) and Domain III (π: 0.003). Z-test indicated negative (purifying) selection of the gene. Combined alignment analysis at the amino acid level for the Peninsular Malaysia and Sarawak PkAMA-1 sequences revealed 34 polymorphic sites. Thirty-one of these sites were dimorphic, and 3 were trimorphic. The amino acid sequences could be categorised into 31 haplotypes. In the haplotype network, PkAMA-1 from Peninsular Malaysia and Sarawak were separated into two groups.
    Matched MeSH terms: Genetic Variation*
  18. Genetic diversity of secreted protein with an altered thrombospondin repeat (SPATR) of Plasmodium knowlesi clinical isolates from Malaysia
    Azlan UW, Lau YL, Hamid MHA, Jelip J, Ooi CH, Mudin RN, et al.
    Trop Biomed, 2022 Dec 01;39(4):504-510.
    PMID: 36602208 DOI: 10.47665/tb.39.4.006
    The Plasmodium knowlesi secreted protein with an altered thrombospondin repeat (PkSPATR) is an important protein that helps in the parasite's invasion into the host cell. This protein has been regarded as one of the potential vaccine candidates against P. knowlesi infection. This study investigates the genetic diversity and natural selection of PkSPATR gene of P. knowlesi clinical isolates from Malaysia. PCR amplification of the full length PkSPATR gene was performed on 60 blood samples of infected P. knowlesi patients from Peninsular Malaysia and Malaysian Borneo. The amplified PCR products were cloned and sequenced. Sequence analysis of PkSPATR from Malaysia showed higher nucleotide diversity (CDS p: 0.01462) than previously reported Plasmodium vivax PvSPATR (p = 0.0003). PkSPATR from Peninsular Malaysia was observed to have slightly higher diversity (CDS p: 0.01307) than those from Malaysian Borneo (CDS p: 0.01212). Natural selection analysis on PkSPATR indicated significant purifying selection. Multiple amino acid sequence alignment revealed 69 polymorphic sites. The phylogenetic tree and haplotype network did not show any distinct clustering of PkSPATR. The low genetic diversity level, natural selection and absence of clustering implied functional constrains of the PkSPATR protein.
    Matched MeSH terms: Genetic Variation
  19. Bovine anaplasmosis: A systematic review with meta-analysis on the global prevalence
    Trop Biomed, 2023 Dec 01;40(4):375-382.
    PMID: 38308823 DOI: 10.47665/tb.40.4.001
    Bovine anaplasmosis, caused by Anaplasma marginale, is a significant infectious disease affecting cattle populations globally. However, the prevalence and distribution of bovine anaplasmosis vary across regions, making it crucial to assess its global burden systematically. This study aims to provide a comprehensive understanding of the global prevalence of bovine anaplasmosis and synthesized data from diverse geographic regions. A literature search was conducted to identify all relevant published articles reporting the prevalence of bovine anaplasmosis and a total of 164 studies were found eligible for final systematic review and meta-analysis. Meta-analysis was conducted using meta package of R software and summary estimates of the prevalence were calculated. Meta-analysis of 129,851 samples from 42 countries was conducted and the overall estimated prevalence of bovine anaplasmosis was found to be 38% (100% CI = 33% - 42%). The prevalence was found to be higher in cattle (39.9%) in comparison to yaks (6.4%). Diagnosis using serology (40.2%) yielded a higher prevalence compared to molecular testing (38.3%) and blood smears (22.4%) methods. Additionally, there were significant differences in the prevalence of bovine anaplasmosis between different countries (p<0.05). This study will inform evidence-based strategies for control and prevention of bovine anaplasmosis on a global scale by discovering the true extent of the disease and identifying high-prevalence areas.
    Matched MeSH terms: Genetic Variation
  20. Genetic dynamics of Salmonella typhi--diversity in clonality
    Pang T
    Trends Microbiol., 1998 Sep;6(9):339-42.
    PMID: 9778724
    Matched MeSH terms: Genetic Variation*
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