Displaying publications 101 - 120 of 1822 in total

Abstract:
Sort:
  1. Thapa BR, Omar AR, Arshad SS, Hair-Bejo M
    Avian Pathol, 2004 Jun;33(3):359-63.
    PMID: 15223566
    Previously we have shown that avian leukosis virus subgroup J (ALV-J) might be present in chicken flocks from Malaysia based on serological study and also on detection of tissue samples with myelocytic infiltration. In this study, the polymerase chain reaction was used to detect ALV-J sequences from archived frozen samples. Out of 21 tissue samples examined, 16 samples were positive for proviral DNA and four samples for ALV-J RNA. However, only nine samples were found positive for myelocytic infiltration. A total of 465 base pairs equivalent to positions 5305 to 5769 of HPRS-103 from each of the viral RNA positive samples were characterized. Sequence analysis indicated that the samples showed high identity (95.9 to 98.2%) and were close to HPRS-103 with identities between 97.4 and 99.3%. This study indicates that ALV-J-specific sequences can be detected by polymerase chain reaction from frozen tissue samples with and without myelocytic infiltration.
    Matched MeSH terms: Phylogeny
  2. 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: Phylogeny*
  3. Wright TF, Johns PM, Walters JR, Lerner AP, Swallow JG, Wilkinson GS
    Genet. Res., 2004 Aug;84(1):27-40.
    PMID: 15663256
    Microsatellite primers are often developed in one species and used to assess neutral variability in related species. Such analyses may be confounded by ascertainment bias (i.e. a decline in amplification success and allelic variability with increasing genetic distance from the source of the microsatellites). In addition, other factors, such as the size of the microsatellite, whether it consists of perfect or interrupted tandem repeats, and whether it is autosomal or X-linked, can affect variation. To test the relative importance of these factors on microsatellite variation, we examine patterns of amplification and allelic diversity in 52 microsatellite loci amplified from five individuals in each of six populations of Cyrtodiopsis stalk-eyed flies that range from 2.2 % to 11.2% mitochondrial DNA sequence divergence from the population used for microsatellite development. We find that amplification success and most measures of allelic diversity declined with genetic distance from the source population, in some cases an order of magnitude faster than in birds or mammals. The median and range of the repeat array length did not decline with genetic distance. In addition, for loci on the X chromosome, we find evidence of lower observed heterozygosity compared with loci on autosomes. The differences in variability between X-linked and autosomal loci are not adequately explained by differences in effective population sizes of the chromosomes. We suggest, instead, that periodic selection events associated with X-chromosome meiotic drive, which is present in many of these populations, reduces X-linked variation.
    Matched MeSH terms: Phylogeny
  4. Bhassu S, Yusoff K, Panandam JM, Embong WK, Oyyan S, Tan SG
    Biochem Genet, 2004 Aug;42(7-8):217-29.
    PMID: 15487586
    The genetic make-up of five populations of Oreochromis spp. was examined by microsatellite analysis. Eleven polymorphic microsatellite loci showed significant departures from the Hardy-Weinberg equilibrium. The mean heterozygosity ranged from 0.6280 to 0.7040 for each population. The genetic distance values showed a clear separation between O. niloticus and O. mossambicus. The differentiation of the O. niloticus populations was then tested with various genetic measures, which are based on both the Infinite Allele and the Stepwise Mutation models. All these measures grouped the populations similarly.
    Matched MeSH terms: Phylogeny
  5. Chan YF, AbuBaker S
    Emerg Infect Dis, 2004 Aug;10(8):1468-70.
    PMID: 15496251
    Hand, foot and mouth disease (HFMD) is a common illness of infants and young children <10 years of age. It is characterized by fever, ulcers in the oral cavity, and rashes with blisters that appear on the palm and sole. The most common causal agents of HFMD are coxsackievirus A16 (CV-A16) and human enterovirus 71 (HEV71), but other enteroviruses, including CV-A5 and CV-A10, can also cause it. When caused by CV-A16 infection, it is usually a mild disease, and patients normally recover without requiring any special medical attention.
    Matched MeSH terms: Phylogeny
  6. Thong KL, Lai KS, Ganeswrie R, Puthucheary SD
    Jpn J Infect Dis, 2004 Oct;57(5):206-9.
    PMID: 15507777
    Over a period of 6 months from January to June 2002, an unusual increase in the isolation of highly resistant Pseudomonas aeruginosa strains was observed in the various wards and intensive care units of a large general hospital in Johor Bahru, Malaysia. An equal number of multidrug resistant (MDR) and drug-susceptible strains were collected randomly from swabs, respiratory specimens, urine, blood, cerebral spinal fluid, and central venous catheters to determine the clonality and genetic variation of the strains. Macrorestriction analysis by pulsed-field gel electrophoresis showed that the 19 MDR strains were genetically very homogenous; the majority showed the dominant profile S1 (n = 10), the rest very closely related profiles S1a (n = 1), S2 (n = 4), and S2a (n = 3), indicating the endemicity of these strains. In contrast, the 19 drug-sensitive strains isolated during the same time period were genetically more diverse, showing 17 pulsed-field profiles (F = 0.50-1.00), and probably derived from the patients themselves. The presence of the MDR clone poses serious therapeutic problems as it may become endemic in the hospital and give rise to future clonal outbreaks. There is also the potential for wider geographical spread.
    Matched MeSH terms: Phylogeny
  7. Beaucournu JC, Wells K
    Parasite, 2004 Dec;11(4):373-7.
    PMID: 15638138
    Medwayella traubiana n. sp., M. pfeifferi n. sp. and M. sabahae n. sp. (Pygiopsyllidae) are described from Sabah (north of Borneo island), the first two on Tupaia tana (Scandentia), the last on Sundasciurus lowii (Rodentia). Sex male is only identified, because these fleas have been collected in sympatry, or even in syntopy. Their determination is based on segment IX and aedeagus. If M. traubiana and M. pfeifferi are related to some known species, M. sabahae is clearly distinct from other Medwayella.
    Matched MeSH terms: Phylogeny
  8. Wang X, Xie Y, Zhou X
    Virus Genes, 2004 Dec;29(3):303-9.
    PMID: 15550769
    Six papaya samples showing downward leaf curling were collected in Guangdong and Guangxi provinces, China. The result of TAS-ELISA showed they were all infected by geminiviruses. Comparison of partial DNA-A sequences reveals that these virus isolates can be classified into two groups. Group I includes isolates G2, G4, G5, G28 and G29 from Guangxi province, while isolate GD2 from Guangdong province belongs to Group II. The complete DNA-A sequence of G2 and GD2 were characterized. Sequence comparisons showed that the DNA-A of G2 and GD2 were most closely related to that of Ageratum yellow vein China virus- [Hn2] and Ageratum yellow vein virus , respectively, with 83.4 and 75.2% nucleotide sequence identity, while DNA-A sequence between G2 and GD2 had only 73.4% sequence identity. The molecular data suggests that G2 and GD2 are two distinct begomoviruses, for which the name Papaya leaf curl China virus (PaLCuCNV) for G2 and Papaya leaf curl Guangdong virus (PaLCuGDV) for GD2 are proposed. Comparison of individual encoded proteins showed the coat protein of G2 and GD2 shared highest amino acid sequence identity (97.7 and 94.2%, respectively) with that of Pepper leaf curl virus -[Malaysia] (PepLCV-[MY]), suggesting the CP of these viruses may have identical ancestor.
    Matched MeSH terms: Phylogeny
  9. Campbell P, Schneider CJ, Adnan AM, Zubaid A, Kunz TH
    Mol Phylogenet Evol, 2004 Dec;33(3):764-81.
    PMID: 15522802
    Taxonomic relationships within the Old World fruit bat genus, Cynopterus, have been equivocal for the better part of a century. While nomenclature has been revised multiple times on the basis of phenotypic characters, evolutionary relationships among taxa representing the entire geographic range of the genus have not been determined. We used mitochondrial DNA sequence data to infer phylogenetic relationships among the three most broadly distributed members of the genus: C. brachyotis, C. horsfieldi, and C. sphinx, and to assess whether C. brachyotis represents a single widespread species, or a complex of distinct lineages. Results clearly indicate that C. brachyotis is a complex of lineages. C. sphinx and C. horsfieldi haplotypes formed monophyletic groups nested within the C. brachyotis species complex. We identified six divergent mitochondrial lineages that are currently referred to C. brachyotis. Lineages from India, Myanmar, Sulawesi, and the Philippines are geographically well-defined, while in Malaysia two lineages, designated Sunda and Forest, are broadly sympatric and may be ecologically distinct. Demographic analyses of the Sunda and Forest lineages suggest strikingly different population histories, including a recent and rapid range expansion in the Sunda lineage, possibly associated with changes in sea levels during the Pleistocene. The resolution of the taxonomic issues raised in this study awaits combined analysis of morphometric characters and molecular data. However, since both the Indian and Malaysian Forest C. brachyotis lineages are apparently ecologically restricted to increasingly fragmented forest habitat, we suggest that reevaluation of the conservation status of populations in these regions should be an immediate goal.
    Matched MeSH terms: Phylogeny
  10. AbuBakar S, Chang LY, Ali AR, Sharifah SH, Yusoff K, Zamrod Z
    Emerg Infect Dis, 2004 Dec;10(12):2228-30.
    PMID: 15663869
    Nipah viruses from pigs from a Malaysian 1998 outbreak were isolated and sequenced. At least two different Nipah virus strains, including a previously unreported strain, were identified. The findings highlight the possibility that the Malaysia outbreaks had two origins of Nipah virus infections.
    Matched MeSH terms: Phylogeny
  11. Hasmah MS, Omar AR, Wan KF, Hair-Bejo M, Aini I
    Acta Virol., 2004;48(2):85-9.
    PMID: 15462283
    It has been shown that a chicken anemia virus (CAV) isolates which had undergone 60 passages in MSB-1 cells (SMSC-1/P60, 3-1/P60) acquired 33-66 nucleotide substitutions at the coding region resulting in 13-16 amino acid changes as compared to the CAV isolates passaged only 5 times in MSB-1 cells (SMSC-1 and 3-1) (Chowdhury et al., Arch. Virol. 148, 2437-2448, 2003). In this study we found that a low CAV (BL-5) and a high CAV passage (BL-5/P90) differed by only 15 nucleotide substitutions resulting in 11 amino acid changes. Phylogenetic analysis based on VP1 also revealed that both isolates were close to each other but not to other CAV isolates from Malaysia, namely SMSC-1 and 3-1.
    Matched MeSH terms: Phylogeny
  12. Tan DY, Hair-Bejo M, Omar AR, Aini I
    Avian Dis, 2004 Apr-Jun;48(2):410-6.
    PMID: 15283430
    The characteristics of the pathogenic infectious bursal disease virus (IBDV) that infected avian species other than commercial chickens were largely unknown. In this study, by using in vivo and molecular methods, we had characterized an IBDV isolate (named 94268) isolated from an infectious bursal disease (IBD) outbreak in Malaysian village chickens--the adulterated descendant of the Southeast Asian jungle fowl (Gallus bankiva) that were commonly reared in the backyard. The 94268 isolate was grouped as the very virulent IBDV (vvIBDV) strain because it caused severe lesions and a high mortality rate in village chickens (>88%) and experimentally infected specific-pathogen-free chickens (>66%). In addition, it possessed all of the vvIBDV molecular markers in its VP2 gene. Phylogenetic analysis using distance, maximum parsimony, and maximum likelihood methods revealed that 94268 was monophyletic with other vvIBDV isolates and closely related to the Malaysian vvIBDV isolates. Given that the VP2 gene of 94268 isolate was almost identical and evolutionarily closely related to other field IBDV isolates that affected the commercial chickens, we therefore concluded that IBD infections had spread across the farm boundary. IBD infection in the village chicken may represent an important part of the IBD epidemiology because these birds could harbor the vvIBDV strain and should not be overlooked in the control and prevention of the disease.
    Matched MeSH terms: Phylogeny
  13. Tee KK, Pon CK, Kamarulzaman A, Ng KP
    AIDS, 2005 Jan 28;19(2):119-26.
    PMID: 15668536
    OBJECTIVES: To investigate the molecular epidemiology of HIV-1 and to screen for the emergence of intersubtype recombinants in Kuala Lumpur, Malaysia.

    DESIGN: A molecular epidemiology study was conducted among HIV-1 seropositive patients attending the University Malaya Medical Center (UMMC) from July 2003 to June 2004.

    METHODS: Protease (PR) and reverse transcriptase (RT) gene sequences were derived from drug resistance genotyping assay of 100 newly diagnosed or antiretroviral-naive patients. These were phylogenetically analysed to determine the subtypes and recombination breakpoint analyses were performed on intersubtype recombinants to estimate the recombination breakpoint(s).

    RESULTS: CRF01_AE predominated in Kuala Lumpur with 65% in both PR and RT genes. B subtype was detected at 14% and 12% in PR and RT genes, respectively. C subtype was present at 1% in both genes. Overall, the concordance of PR and RT genes in discriminating subtypes/circulating recombinant forms (CRF) was high at 96%. In this study, novel CRF01_AE/B intersubtype recombinants were detected at high prevalence (22%), including those isolates with subtype discordance. Thai variants of CRF01_AE and B subtype were involved in the genesis of these unique recombinant forms (URF). Interestingly, 19 CRF01_AE/B intersubtype recombinant isolates shared similar recombination breakpoints in both PR and RT genes. Several distinct URF were also identified.

    CONCLUSION: PR and RT genes can be utilized for subtype/CRF assessment with high degree of agreement, allowing concurrent surveillance of circulating HIV-1 subtypes with antiretroviral drug resistance genotyping tests. The emergence of highly identical CRF01_AE/B intersubtype recombinants suggests the possibility of the appearance of a new circulating recombinant form in Kuala Lumpur.

    Matched MeSH terms: Phylogeny
  14. Yuan YM, Wohlhauser S, Möller M, Klackenberg J, Callmander M, Küpfer P
    Syst Biol, 2005 Feb;54(1):21-34.
    PMID: 15805008
    Disjunctive distributions across paleotropical regions in the Indian Ocean Basin (IOB) often invoke dispersal/vicariance debates. Exacum (Gentianaceae, tribe Exaceae) species are spread around the IOB, in Africa, Madagascar, Socotra, the Arabian peninsula, Sri Lanka, India, the Himalayas, mainland Southeast Asia including southern China and Malaysia, and northern Australia. The distribution of this genus was suggested to be a typical example of vicariance resulting from the breakup of the Gondwanan supercontinent. The molecular phylogeny of Exacum is in principle congruent with morphological conclusions and shows a pattern that resembles a vicariance scenario with rapid divergence among lineages, but our molecular dating analysis demonstrates that the radiation is too recent to be associated with the Gondwanan continental breakup. We used our dating analysis to test the results of DIVA and found that the program predicted impossible vicariance events. Ancestral area reconstruction suggests that Exacum originated in Madagascar, and divergence dating suggests its origin was not before the Eocene. The Madagascan progenitor, the most recent common ancestor of Exacum, colonized Sri Lanka and southern India via long-distance dispersals. This colonizer underwent an extensive range expansion and spread to Socotra-Arabia, northern India, and mainland Southeast Asia in the northern IOB when it was warm and humid in these regions. This widespread common ancestor retreated subsequently from most parts of these regions and survived in isolation in Socotra-Arabia, southern India-Sri Lanka, and perhaps mainland Southeast Asia, possibly as a consequence of drastic climatic changes, particularly the spreading drought during the Neogene. Secondary diversification from these surviving centers and Madagascar resulted in the extant main lineages of the genus. The vicariance-like pattern shown by the phylogeny appears to have resulted from long-distance dispersals followed by extensive range expansion and subsequent fragmentation. The extant African species E. oldenlandioides is confirmed to be recently dispersed from Madagascar.
    Matched MeSH terms: Phylogeny*
  15. Chua PK, Corkill JE, Hooi PS, Cheng SC, Winstanley C, Hart CA
    Emerg Infect Dis, 2005 Feb;11(2):271-7.
    PMID: 15752446
    An obligate intracellular bacterium was isolated from urine samples from 7 (3.5%) of 202 fruit bats (Eonycteris spelaea) in peninsular Malaysia. The bacterium produced large membrane-bound inclusions in human, simian, and rodent cell lines, including epithelial, fibroblastlike, and lymphoid cells. Thin-section electron microscopy showed reticulate bodies dividing by binary fission and elementary bodies in the inclusions; mitochondria surrounded the inclusions. The inclusions were positive for periodic acid-Schiff stain but could not be stained by fluorescein-labeled anti-Chlamydia trachomatis major outer membrane protein monoclonal antibody. The bacterium was resistant to penicillin and streptomycin (MICs > 256 mg/L) but susceptible to tetracycline (MIC = 0.25 mg/L) and chloramphenicol (MIC = 0.5 mg/L). Sequence analysis of the 16SrRNA gene indicated that it was most closely related to 2 isolates of Waddlia chondrophila (94% and 96% identity). The 16S and 23S rRNA gene signatures were only 91% identical. We propose this novel bacterium be called W. malaysiensis.
    Matched MeSH terms: Phylogeny
  16. Matsuzaki Y, Sato K, Sugawara K, Takashita E, Muraki Y, Morishita T, et al.
    J Clin Microbiol, 2005 Feb;43(2):993-5.
    PMID: 15695727
    An influenza C virus was isolated from a Japanese traveler who had visited Malaysia in April 1999. Phylogenetic analysis indicated that the genome composition of this virus was distinct from that of any other strain isolated in Japan. The possibility that a genetically unique influenza C virus was introduced into Japan by a traveler is shown.
    Matched MeSH terms: Phylogeny
  17. Dussart P, Cartet G, Huguet P, Lévêque N, Hajjar C, Morvan J, et al.
    J Med Virol, 2005 Apr;75(4):559-65.
    PMID: 15714481
    An outbreak of acute hemorrhagic conjunctivitis occurred in French Guiana between April and July 2003, with approximately 6,000 cases in the two major cities Kourou and Cayenne. Since acute hemorrhagic conjunctivitis is not a notifiable disease in France, there was no registration of the number of cases. Therefore, these were estimated by comparing the consumption of antibiotic eye drops and ophthalmic ointments during 2002 and 2003. The outbreak rapidly spread into the Caribbean Islands, causing an outbreak in Guadeloupe in October. Viral isolates from conjunctival swabs of 16 patients were confirmed to be enterovirus by PCR directed to the 5' UTR of the genome. The isolates could not be neutralized by the Melnick intersecting pools, but were shown to be CV-A24 variant by limited sequencing within the VP1 and 3C regions of 12 strains. Phylogenetic analysis revealed that they were similar to the genotype III strains causing outbreaks in Korea 2002 and Malaysia 2003. The previous outbreak of conjunctivitis caused by CV-A24 in the Caribbean in the 1980s was also introduced from Asia, and disappeared after 3 years. This new introduction from Asia and its rapid spread into the Caribbean, where the infection disappeared after a few months, indicates that the CV-A24 variant has a different epidemiological pattern in this region compared to South East Asia, since it has not established an endemic infection. It had to be reintroduced from Asia, where it has been circulating since the 1970s.
    Matched MeSH terms: Phylogeny*
  18. Leisner JJ, Vancanneyt M, Van der Meulen R, Lefebvre K, Engelbeen K, Hoste B, et al.
    Int J Syst Evol Microbiol, 2005 May;55(Pt 3):1267-1270.
    PMID: 15879266 DOI: 10.1099/ijs.0.63434-0
    Three lactic acid bacterial (LAB) strains obtained from a Malaysian acid-fermented condiment, tempoyak (made from pulp of the durian fruit), showed analogous but distinct patterns after screening by SDS-PAGE of whole-cell proteins and comparison with profiles of all recognized LAB species. 16S rRNA gene sequencing of one representative strain showed that the taxon belongs phylogenetically to the genus Leuconostoc, with its nearest neighbour being Leuconostoc fructosum (98 % sequence similarity). Biochemical characteristics and DNA-DNA hybridization experiments demonstrated that the strains differ from Leuconostoc fructosum and represent a single, novel Leuconostoc species for which the name Leuconostoc durionis sp. nov. is proposed. The type strain is LMG 22556(T) (= LAB 1679(T) = D-24(T) = CCUG 49949(T)).
    Matched MeSH terms: Phylogeny
  19. Macaulay V, Hill C, Achilli A, Rengo C, Clarke D, Meehan W, et al.
    Science, 2005 May 13;308(5724):1034-6.
    PMID: 15890885
    A recent dispersal of modern humans out of Africa is now widely accepted, but the routes taken across Eurasia are still disputed. We show that mitochondrial DNA variation in isolated "relict" populations in southeast Asia supports the view that there was only a single dispersal from Africa, most likely via a southern coastal route, through India and onward into southeast Asia and Australasia. There was an early offshoot, leading ultimately to the settlement of the Near East and Europe, but the main dispersal from India to Australia approximately 65,000 years ago was rapid, most likely taking only a few thousand years.
    Matched MeSH terms: Phylogeny
  20. Li L, He Y, Yang H, Zhu J, Xu X, Dong J, et al.
    J Clin Microbiol, 2005 Aug;43(8):3835-9.
    PMID: 16081920
    The genetic and phylogenetic characteristics of human enterovirus 71 (EV71) and coxsackievirus A16 (CA16) sampled from children with hand, foot, and mouth disease in Shenzhen, People's Republic of China, over a 6-year period (1999 to 2004) were examined with reverse transcription-PCR and DNA sequencing. Out of 147 stool specimens, 60 showed positive signals when screened with EV71- and CA16-specific primers. EV71 was identified in 19 specimens, and CA16 was identified in 41 specimens; coinfection by EV71 and CA16 was not observed. Phylogenetic analysis of all EV71 strains isolated from the mainland Chinese samples established C4 as the predominant genotype. Only one other known strain (3254-TAI-98; AF286531), isolated in Taiwan in 1998, was identified as belonging to genotype C4. Phylogenetic analysis of CA16 strains allowed us to identify three new genetic lineages (A, B, and C), with lineage C recently predominating in Asian countries, such as the People's Republic of China, Malaysia, and Japan. These new observations indicate that CA16 circulating in the People's Republic of China is genetically diverse, and additional surveillance is warranted.
    Matched MeSH terms: Phylogeny
Filters
Contact Us

Please provide feedback to Administrator (afdal@afpm.org.my)

External Links