Displaying publications 401 - 420 of 571 in total

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  1. Preliminary survey of Capillaria hepatica (Bancroft, 1893) in Malaysia
    Sinniah B, Singh M, Anuar K
    J Helminthol, 1979 Jun;53(2):147-52.
    PMID: 479546
    The prevalence of Capillaria hepatica (Bancroft, 1893) infection in a total of 2324 rats trapped from 25 localities in West Malaysia was 15.5%. Infection rates in males (16.0%) and females (15.1%) are similar. A significantly higher percentage of adults (18.1%) than young (7.7%) was infected. Capillaria hepatica infection rates among urban (0.7%) and jungle (0.0%) rats was very low as compared to field rats (17.7%) trapped from agricultural areas such as oil palm estates and rice growing areas. Prevalence of C. hepatica infection in rats is not evenly distributed throughout West Malaysia. There seem to be localised foci of infection. In some areas as many as 77.8% of the adult rats are found to be infected while in other areas the same species of rats are found free of infection.
    Matched MeSH terms: Species Specificity
  2. Fulltext Genome sequence of an unclassified pleosporales species isolated from human nasopharyngeal aspirate
    Ng KP, Yew SM, Chan CL, Soo-Hoo TS, Na SL, Hassan H, et al.
    Eukaryot Cell, 2012 Jun;11(6):828.
    PMID: 22645233 DOI: 10.1128/EC.00133-12
    Pleosporales is the largest order in the fungal class Dothideomycetes. We report the 36,814,818-bp draft genome sequence and gene annotation of UM1110, a Pleosporales isolate associated with unclassified genera that is potentially a new fungal species. Analysis of the genome sequence led to the finding of genes associated with fungal adhesive proteins, secreted proteases, allergens, and pseudohyphal development.
    Matched MeSH terms: Species Specificity
  3. Fulltext Genome sequence of Aureobasidium pullulans AY4, an emerging opportunistic fungal pathogen with diverse biotechnological potential
    Chan GF, Bamadhaj HM, Gan HM, Rashid NA
    Eukaryot Cell, 2012 Nov;11(11):1419-20.
    PMID: 23104371 DOI: 10.1128/EC.00245-12
    Aureobasidium pullulans AY4 is an opportunistic pathogen that was isolated from the skin of an immunocompromised patient. We present here the draft genome of strain AY4, which reveals an abundance of genes relevant to bioindustrial applications, including biocontrol and biodegradation. Putative genes responsible for the pathogenicity of strain AY4 were also identified.
    Matched MeSH terms: Species Specificity
  4. Variation of C-bands in the chromosomes of several subspecies of Rattus rattus
    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: Species Specificity
  5. Fulltext Habitat degradation and indiscriminate hunting differentially impact faunal communities in the Southeast Asian tropical biodiversity hotspot
    Tilker A, Abrams JF, Mohamed A, Nguyen A, Wong ST, Sollmann R, et al.
    Commun Biol, 2019;2:396.
    PMID: 31701025 DOI: 10.1038/s42003-019-0640-y
    Habitat degradation and hunting have caused the widespread loss of larger vertebrate species (defaunation) from tropical biodiversity hotspots. However, these defaunation drivers impact vertebrate biodiversity in different ways and, therefore, require different conservation interventions. We conducted landscape-scale camera-trap surveys across six study sites in Southeast Asia to assess how moderate degradation and intensive, indiscriminate hunting differentially impact tropical terrestrial mammals and birds. We found that functional extinction rates were higher in hunted compared to degraded sites. Species found in both sites had lower occupancies in the hunted sites. Canopy closure was the main predictor of occurrence in the degraded sites, while village density primarily influenced occurrence in the hunted sites. Our findings suggest that intensive, indiscriminate hunting may be a more immediate threat than moderate habitat degradation for tropical faunal communities, and that conservation stakeholders should focus as much on overhunting as on habitat conservation to address the defaunation crisis.
    Matched MeSH terms: Species Specificity
  6. Changes in photosynthesis and leaf characteristics with tree height in five dipterocarp species in a tropical rain forest
    Kenzo T, Ichie T, Watanabe Y, Yoneda R, Ninomiya I, Koike T
    Tree Physiol, 2006 Jul;26(7):865-73.
    PMID: 16585032
    Variations in leaf photosynthetic, morphological and biochemical properties with increasing plant height from seedlings to emergent trees were investigated in five dipterocarp species in a Malaysian tropical rain forest. Canopy openness increased significantly with tree height. Photosynthetic properties, such as photosynthetic capacity at light saturation, light compensation point, maximum rate of carboxylation and maximum rate of photosynthetic electron transport, all increased significantly with tree height. Leaf morphological and biochemical traits, such as leaf mass per area, palisade layer thickness, nitrogen concentration per unit area, chlorophyll concentration per unit dry mass and chlorophyll to nitrogen ratio, also changed significantly with tree height. Leaf properties had simple and significant relationships with tree height, with few intra- and interspecies differences. Our results therefore suggest that the photosynthetic capacity of dipterocarp trees depends on tree height, and that the trees adapt to the light environment by adjusting their leaf morphological and biochemical properties. These results should aid in developing models that can accurately estimate carbon dioxide flux and biomass production in tropical rain forests.
    Matched MeSH terms: Species Specificity
  7. Fulltext Identification of potential Campylobacter jejuni genes involved in biofilm formation by EZ-Tn5 Transposome mutagenesis
    Teh AHT, Lee SM, Dykes GA
    BMC Res Notes, 2017 May 12;10(1):182.
    PMID: 28499399 DOI: 10.1186/s13104-017-2504-1
    BACKGROUND: Biofilm formation has been suggested to play a role in the survival of Campylobacter jejuni in the environment and contribute to the high incidence of human campylobacteriosis. Molecular studies of biofilm formation by Campylobacter are sparse.

    RESULTS: We attempted to identify genes that may be involved in biofilm formation in seven C. jejuni strains through construction of mutants using the EZ-Tn5 Transposome system. Only 14 mutants with reduced biofilm formation were obtained, all from one strain of C. jejuni. Three different genes of interest, namely CmeB (synthesis of multidrug efflux system transporter proteins), NusG (transcription termination and anti-termination protein) and a putative transmembrane protein (involved in membrane protein function) were identified. The efficiency of the EZ::TN5 transposon mutagenesis approach was strain dependent and was unable to generate any mutants from most of the strains used.

    CONCLUSIONS: A diverse range of genes may be involved in biofilm formation by C. jejuni. The application of the EZ::TN5 system for construction of mutants in different Campylobacter strains is limited.

    Matched MeSH terms: Species Specificity
  8. Fulltext Comparison of eight complete chloroplast genomes of the endangered Aquilaria tree species (Thymelaeaceae) and their phylogenetic relationships
    Hishamuddin MS, Lee SY, Ng WL, Ramlee SI, Lamasudin DU, Mohamed R
    Sci Rep, 2020 Aug 03;10(1):13034.
    PMID: 32747724 DOI: 10.1038/s41598-020-70030-0
    Aquilaria tree species are naturally distributed in the Indomalesian region and are protected against over-exploitation. They produce a fragrant non-timber product of high economic value, agarwood. Ambiguous species delimitation and limited genetic information within Aquilaria are among the impediments to conservation efforts. In this study, we conducted comparative analysis on eight Aquilaria species complete chloroplast (cp) genomes, of which seven were newly sequenced using Illumina HiSeq X Ten platform followed by de novo assembly. Aquilaria cp genomes possess a typical quadripartite structure including gene order and genomic structure. The length of each of the cp genome is about 174 kbp and encoded between 89 and 92 proteins, 38 tRNAs, and 8 rRNAs, with 27 duplicated in the IR (inverted repeat) region. Besides, 832 repeats (forward, reverse, palindrome and complement repeats) and nine highly variable regions were also identified. The phylogenetic analysis suggests that the topology structure of Aquilaria cp genomes were well presented with strong support values based on the cp genomes data set and matches their geographic distribution pattern. In summary, the complete cp genomes will facilitate development of species-specific molecular tools to discriminate Aquilaria species and resolve the evolutionary relationships of members of the Thymelaeaceae family.
    Matched MeSH terms: Species Specificity
  9. Fulltext Ecological impacts of tropical forest fragmentation: how consistent are patterns in species richness and nestedness?
    Hill JK, Gray MA, Khen CV, Benedick S, Tawatao N, Hamer KC
    Philos Trans R Soc Lond B Biol Sci, 2011 Nov 27;366(1582):3265-76.
    PMID: 22006967 DOI: 10.1098/rstb.2011.0050
    Large areas of tropical forest now exist as remnants scattered across agricultural landscapes, and so understanding the impacts of forest fragmentation is important for biodiversity conservation. We examined species richness and nestedness among tropical forest remnants in birds (meta-analysis of published studies) and insects (field data for fruit-feeding Lepidoptera (butterflies and moths) and ants). Species-area relationships were evident in all four taxa, and avian and insect assemblages in remnants typically were nested subsets of those in larger areas. Avian carnivores and nectarivores and predatory ants were more nested than other guilds, implying that the sequential loss of species was more predictable in these groups, and that fragmentation alters the trophic organization of communities. For butterflies, the ordering of fragments to achieve maximum nestedness was by fragment area, suggesting that differences among fragments were driven mainly by extinction. In contrast for moths, maximum nestedness was achieved by ordering species by wing length; species with longer wings (implying better dispersal) were more likely to occur at all sites, including low diversity sites, suggesting that differences among fragments were driven more strongly by colonization. Although all four taxa exhibited high levels of nestedness, patterns of species turnover were also idiosyncratic, and thus even species-poor sites contributed to landscape-scale biodiversity, particularly for insects.
    Matched MeSH terms: Species Specificity
  10. Floral phenylpropanoid cocktail and architecture of Bulbophyllum vinaceum orchid in attracting fruit flies for pollination
    Tan KH, Tan LT, Nishida R
    J Chem Ecol, 2006 Nov;32(11):2429-41.
    PMID: 17082990 DOI: 10.1007/s10886-006-9154-4
    It is widely believed that most orchid flowers attract insects by using deception or chemical rewards in the form of nectar. Flowers of Bulbophyllum vinaceum produce a large array of phenylpropanoids that lure tephritid fruit fly males and also act as floral reward, which the flies subsequently convert to pheromone components. The major floral volatile components identified are methyl eugenol (ME), trans-coniferyl alcohol (CF), 2-allyl-4,5-dimethoxphenol (DMP), and trans-3,4-dimethoxycinnamyl acetate, whereas the minor components are eugenol, euasarone, trans-3,4-dimethoxy cinnamyl alcohol, and cis-coniferyl alcohol. Among the various floral parts, the lip (which is held in a closed position up against the sexual organs) has the highest concentration of the major compounds. An attracted male fly normally lands on one of the petals before climbing up onto and forcing the "spring loaded" floral lip into the open position, hence exposing the floral sexual organs. The architecture and location of chemical attractants of the lip compel the fly to align itself along the lip's longitudinal axis in a precise manner. As the fly laps up the compounds and moves towards the base of the lip, it passes the point of imbalance causing the lip to spring back to its normal closed position. The fly is catapulted headfirst into the column cavity, and its dorsum strikes the protruding sticky base of the hamulus and adheres to it. The momentum of the fly and the structural morphology of the long stiff hamulus act to pry out the pollinia from its anther cover. Hence, the pollinarium (pollinia + hamulus) is detached from the flower and adhered to the fly's dorsum. In this unique mutualistic association, both species receive direct reproductive benefits--the flower's pollinarium is transported for cross pollination, and the fly is offered a bouquet of phenylpropanoids (synomone) that it consumes, converts, and/or sequesters as sex pheromonal components, thus enhancing sexual attraction and mating success.
    Matched MeSH terms: Species Specificity
  11. Interspecific variation in defense secretions of Malaysian termites from the genus Bulbitermes
    Chuah CH
    J Chem Ecol, 2005 Apr;31(4):819-27.
    PMID: 16124253
    The chemicals of the defense secretions of Malaysian Bulbitermes, B. singaporensis, B. germanus, B. sarawakensis, and Bulbitermes sp. B, show that B. singaporensis is distinct from the other species, which are themselves closely related; the genetic distance between B. singaporensis and B. germanus is 0.71. B. singaporensis contains tetracyclic kempane, and B. germanus and B. sarawakensis contain tricyclic trinervitene; Bulbitermes sp. B contains a mixture of kempane and trinervitene. The mono- and diterpenoid compositions are species-specific.
    Matched MeSH terms: Species Specificity
  12. Fulltext Does transovarial transmission of dengue virus occur in Malaysian Aedes aegypti and Aedes albopictus?
    Lee HL, Mustafakamal I, Rohani A
    Southeast Asian J Trop Med Public Health, 1997 Mar;28(1):230-2.
    PMID: 9322311
    Matched MeSH terms: Species Specificity
  13. Fulltext Cockroaches from urban human dwellings: isolation of bacterial pathogens and control
    Vythilingam I, Jeffery J, Oothuman P, Abdul Razak AR, Sulaiman A
    Southeast Asian J Trop Med Public Health, 1997 Mar;28(1):218-22.
    PMID: 9322309
    A study was carried out to determine the distribution of cockroaches in two different housing areas with central sewerage or individual septic tanks in an urban area in Kuala Lumpur, Malaysia. Six species of cockroaches were present and of these Periplaneta americana and Periplaneta brunnea were found in greater abundance. Seventeen species of bacteria were isolated and of these Escherichia coli and Klebsiella p. pneumoniae were isolated in greatest numbers. Control measures carried out using lambda cyhalothrin showed that there was no significant difference between treated and control sites.
    Matched MeSH terms: Species Specificity
  14. Population cytogenetics of the malaria vector Anopheles leucosphyrus group
    Baimai V
    Southeast Asian J Trop Med Public Health, 1988 Dec;19(4):667-80.
    PMID: 3238480
    Until recently, very little was known of Anopheles species complexes and their relationships to epidemiology and malaria transmission in Southeast Asia. During the past eight years, extensive studies on the genetics of natural populations of anopheline mosquitoes in this region, involving the interdisciplinary efforts of taxonomists, operational entomologists and biologists, have revealed groups of cryptic species of Anopheles vectors, particularly the An. leucos phyrus group. This species group comprise seventeen species and two subspecies widely distributed in the forested areas of Southeast Asia. Among these species. An. dirus Peyton and Harrison, has been shown by cytogenetic and morphological studies to be a complex of at least seven isomorphic species, provisionally designated species A, B, C, D, E, F and takasagoensis, on the Southeast Asian mainland. Cytological identification of these species is based on distinct banding patterns of salivary gland polytene chromosomes as well as heterochromatin differences in mitotic karyotypes. The five species found in Thailand (A-D, F) exhibit distinct geographic distributions. Species A is widespread throughout Thailand except in the south. Species B had been found in sympatry with species C in southern Thailand and both seem to show north-south clinal geographic variation. Species D is common on the west side of southern Thailand and along the Thai-Burmese border in sympatry with species A. Species F, An. nemophilous Peyton and Ramalingam, has been found in a population at the Thai-Malaysian border in this study although it was known to be common in southern and western Thailand and Peninsular Malaysia. Species E is known only from western India. The five species found in Thailand also exhibit seasonal variation in relative abundance and different nocturnal biting cycles. Chromosomal polymorphisms have been observed in mitotic and polytene chromosomes of An. dirus A and D. Species B and C also show heterochromatin variation in the sex chromosomes, but are monomorphic for the standard sequence in polytene chromosomes. These biological characteristics of the An. dirus complex may have implications for understanding the epidemiology of malaria in Southeast Asia. Recent cytogenetic studies of wild-caught samples of An. leucosphyrus from Sumatra, Kalimantan and southern Thailand have revealed the presence of two distinct species within this taxon. Species A is widely distributed in southern Thailand, East Malaysia and Kalimantan, while species B is confined to Sumatra. The two isomorphic species are vectors of human malaria within their range of distribution.(ABSTRACT TRUNCATED AT 400 WORDS)
    Matched MeSH terms: Species Specificity
  15. Fulltext House dust mite fauna in the Klang Valley, Malaysia
    Mariana A, Ho TM, Sofian-Azirun M, Wong AL
    Southeast Asian J Trop Med Public Health, 2000 Dec;31(4):712-21.
    PMID: 11414418
    Allergy to house dust mites (HDM) is an important cause of asthma and rhinitis in Malaysia. This study was carried out to evaluate the dust mite fauna in the Klang Valley. Dust samples were collected from 20 houses from March 1994 to February 1995. Thirty-three dust samples from mattresses were examined monthly for the occurrence of HDM. A total of 22 species in 9 families of HDM was identified. The most common and densely populated species was Blomia tropicalis with an average density of 8,934 mites/g of dust. Dermatophagoides pteronyssinus was the next in abundance, followed by Malayoglyphus intermedius. All houses surveyed were found to be infested with HDM and every house had at least 6 species of HDM. B. tropicalis and D. pteronyssinus were found in all mattresses. HDM in the Klang Valley were found to be highly prevalent and present in high densities. In this study, counts of D. pteronyssinus was found to exceed the proposed exposure threshold of 500 mites/g dust, for triggering acute asthma. Although counts of B. tropicalis exceeded D. pteronyssinus, no conclusion could be made because there is currently no exposure threshold for triggering acute asthma, for this species. Monthly distribution of B. tropicalis and D. pteronyssinus showed 2 peaks and 4 peaks, respectively. The major peak for D. pteronysinus was in January 1995 whereas for B. tropicalis, the major peak was more variable and occurred between November 1994 to January 1995. Both the species showed minor peak in April 1994.
    Matched MeSH terms: Species Specificity
  16. Detection and molecular characterization of the zot gene in Vibrio cholerae and V. alginolyticus isolates
    Raja N, Shamsudin MN, Somarny W, Rosli R, Rahim RA, Radu S
    Southeast Asian J Trop Med Public Health, 2001 Mar;32(1):100-4.
    PMID: 11485069
    A total of 11 Vibrio cholerae isolates from 1996-1998 outbreaks in Malaysia and 4 V. alginolyticus were analyzed. Isolates were characterized by polymerase chain reaction (PCR) and Southern hybridization for the presence of the gene encoding zonula occludens toxin (zot). Screening of zot gene by PCR revealed the presence of this gene in V. cholerae and V. alginolyticus. The zot gene from one V. cholerae Ogawa isolate that was cloned in a pCR 2.1 TOPO vector was sequenced. The sequences obtained were 99% homologous to the zot gene sequence from the Gene Bank.
    Matched MeSH terms: Species Specificity
  17. Hepatosplenic lesions induced by experimental Schistosoma malayensis in rabbits
    Shekhar KC, Pathmanathan R
    Southeast Asian J Trop Med Public Health, 1993 Jun;24(2):333-9.
    PMID: 8266238
    Two groups of three rabbits each were infected with 250 cercariae of the Baling and Koyan strain of Schistosoma malayensis. Changes induced by both strains included periportal hepatocellular necrosis and fibrosis. Vascular changes such as portal phlebitis and thrombophlebitis and varying degrees of pericholangitis were also present. Amyloid deposition was noted. A comparative study of the changes induced in rabbits by S. malayensis, S. mekongi and S. japonicum showed that the hepatic lesions induced by the Baling strain of S. malayensis were similar to that induced by S. japonicum, and were more severe than that induced by S. mekongi or the Koyan strain.
    Matched MeSH terms: Species Specificity
  18. Distribution and ecological consideration of Breinlia booliati infecting wild rodents in Malaysia
    Liat LB, Wah MJ, Singh M, Ho BC, Hian YE
    Southeast Asian J Trop Med Public Health, 1975 Jun;6(2):241-6.
    PMID: 1166352
    Seven of the 18 species of lowland forest terrestrial and semi-arboreal murids were found naturally infected with Breinlia booliati. Of these, two species, Rattus sabanus and R. cremoriventer, were found to be the most preferred hosts. None of the murids from the highland, field or human-inhabited areas was infected. This could have been due more to the greater scarcity of the vectors in these habitats than to the susceptibility of the hosts. The absence of this parasite in the squirrels examined may be attributed either to host specificity or to the normal activity cycles or vertical stratification of the vectors, separating them in space and/or time from the squirrels. The pattern of dispersion of the parasite is influenced by the wide distribution of suitable hosts, and the hypothesis that the parasite is of forest origin is discussed.
    Matched MeSH terms: Species Specificity
  19. Dipetalonema digitatum (Chandler 1929) infection in the leaf monkey, Presbytis obscura (Reid)
    Mak JW, Inder-Singh, Yen PK, Yap LF
    Southeast Asian J Trop Med Public Health, 1980 Mar;11(1):141.
    PMID: 6773151
    Matched MeSH terms: Species Specificity
  20. Specific detection of Nipah virus using real-time RT-PCR (TaqMan)
    Guillaume V, Lefeuvre A, Faure C, Marianneau P, Buckland R, Lam SK, et al.
    J Virol Methods, 2004 Sep 15;120(2):229-37.
    PMID: 15288966
    Nipah and Hendra viruses belong to the novel Henipavirus genus of the Paramyxoviridae family. Its zoonotic circulation in bats and recent emergence in Malaysia with fatal consequences for humans that were in close contact with infected pigs, has made the reinforcement of epidemiological and clinical surveillance systems a priority. In this study, TaqMan RT-PCR of the Nipah nucleoprotein has been developed so that Nipah virus RNA in field specimens or laboratory material can be characterized rapidly and specifically and quantitated. The linearity of the standard curve allowed quantification of 10(3) to 10(9) RNA transcripts. The sensitivity of the test was close to 1 pfu. The kinetics of Nipah virus production in Vero cells was monitored by the determination of infectious virus particles in the supernatant fluid and by quantitation of the viral RNA. Approximately, 1000 RNA molecules were detected per virion, suggesting the presence of many non-infectious particles, similar to other RNA viruses. TaqMan real-time RT-PCR failed to detect Hendra virus DNA. Importantly, the method was able to detect virus despite a similar ratio in viremic sera from hamsters infected with Nipah virus. This standardized technique is sensitive and reliable and allows rapid detection and quantitation of Nipah RNA in both field and experimental materials used for the surveillance and specific diagnosis of Nipah virus.
    Matched MeSH terms: Species Specificity
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