Displaying publications 361 - 380 of 663 in total

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  1. Quorum sensing is required for full virulence of Vibrio campbellii towards tiger grouper (Epinephelus fuscoguttatus) larvae
    Noor NM, Defoirdt T, Alipiah N, Karim M, Daud H, Natrah I
    J Fish Dis, 2019 Apr;42(4):489-495.
    PMID: 30742313 DOI: 10.1111/jfd.12946
    The link between quorum sensing in Vibrio campbellii and its virulence towards tiger grouper (Epinephelus fuscoguttatus) was investigated using V. campbellii wild type and quorum-sensing mutants with inactive quorum sensing or constitutively maximal quorum-sensing activity, and signal molecule synthase mutants. The results showed that wild-type V. campbellii is pathogenic to grouper larvae, causing more than 50% mortality after 4 days of challenge. Furthermore, the mortality of larvae challenged with the mutant with maximally active quorum sensing was significantly higher than that of larvae challenged with the wild type, whereas a higher survival was observed in the larvae challenged to the mutant with a completely inactive quorum-sensing system. Grouper larvae challenged with either the signal molecule synthase triple mutant, the harveyi autoinducer-1 (HAI-1) synthase mutant and the autoinducer-2 (AI-2) synthase mutant showed higher survival than larvae challenged with the wild type. In contrast, larvae challenged with the cholerae autoinducer-1 (CAI-1) synthase mutant showed high mortality. This indicates that HAI-1 and AI-2, but not CAI-1, are required for full virulence of V. campbellii towards grouper larvae. Our data suggest that quorum-sensing inhibition could be an effective strategy to control V. campbellii infections in tiger grouper.
    Matched MeSH terms: Larva/microbiology
  2. A New Black Fly Species of the Simulium (Gomphostilbia) duolongum Subgroup (Diptera: Simuliidae) From Vietnam, and Molecular Comparisons With Related Species Using the COI Barcoding Gene
    Takaoka H, Low VL, Tan TK, Ya'cob Z, Sofian-Azirun M, Dhang Chen C, et al.
    J Med Entomol, 2019 02 25;56(2):432-440.
    PMID: 30597034 DOI: 10.1093/jme/tjy222
    Simulium (Gomphostilbia) yvonneae sp. nov. is described based on adults, pupae, and mature larvae from Vietnam. This new species belongs to the Simulium duolongum subgroup in the S. batoense species-group of the subgenus Gomphostilbia Enderlein. It is distinguished by having a relatively larger number of male upper-eye facets in 16 vertical columns and 16 horizontal rows and a pupal gill with eight filaments arranged as 3+(1+2)+2 from dorsal to ventral, of which two filaments of the ventral pair are 1.8 times as long as the longest filament of the middle and dorsal triplets. Morphological comparisons are made to distinguish this new species from all 22 related species. The genetic distinctiveness of this new species in the S. duolongum subgroup is also presented based on the DNA barcoding COI gene.
    Matched MeSH terms: Larva/anatomy & histology
  3. Eristalinus arvorum (Fabricius, 1787) (Diptera: Syrphidae) in Human Skull: A New Fly Species of Forensic Importance
    Heo CC, Rahimi R, Mengual X, M Isa MS, Zainal S, Khofar PN, et al.
    J Forensic Sci, 2020 Jan;65(1):276-282.
    PMID: 31305956 DOI: 10.1111/1556-4029.14128
    A body of an unknown adult female was found within a shallow burial ground in Malaysia whereas the skull was exposed and visible on the ground. During autopsy examination, nine insect larvae were recovered from the interior of the human skull and subsequently preserved in 70% ethanol. The larvae were greyish in appearance, each with a posterior elongated breathing tube. A week after the autopsy, more larvae were collected at the burial site, and some of them were reared into adults. Adult specimens and larvae from the skull and from the burial site were sequenced to obtain DNA barcodes. Results showed all adult flies reared from the burial site, as well as the larvae collected from the skull were identified as Eristalinus arvorum (Fabricius, 1787) (Diptera: Syrphidae). Here, we report the colonization of E. arvorum larvae on a human corpse for the first time.
    Matched MeSH terms: Larva/physiology
  4. Fulltext A neurotoxin that specifically targets Anopheles mosquitoes
    Contreras E, Masuyer G, Qureshi N, Chawla S, Dhillon HS, Lee HL, et al.
    Nat Commun, 2019 06 28;10(1):2869.
    PMID: 31253776 DOI: 10.1038/s41467-019-10732-w
    Clostridial neurotoxins, including tetanus and botulinum neurotoxins, generally target vertebrates. We show here that this family of toxins has a much broader host spectrum, by identifying PMP1, a clostridial-like neurotoxin that selectively targets anopheline mosquitoes. Isolation of PMP1 from Paraclostridium bifermentans strains collected in anopheline endemic areas on two continents indicates it is widely distributed. The toxin likely evolved from an ancestral form that targets the nervous system of similar organisms, using a common mechanism that disrupts SNARE-mediated exocytosis. It cleaves the mosquito syntaxin and employs a unique receptor recognition strategy. Our research has an important impact on the study of the evolution of clostridial neurotoxins and provides the basis for the use of P. bifermentans strains and PMP1 as innovative, environmentally friendly approaches to reduce malaria through anopheline control.
    Matched MeSH terms: Larva/drug effects
  5. Two New Ansonia from Mountains of Borneo (Anura, Bufonidae)
    Matsui M, Nishikawa K, Eto K, Hossman MY
    Zoolog Sci, 2020 Feb;37(1):91-101.
    PMID: 32068378 DOI: 10.2108/zs190078
    Two lineages of stream toads in the genus Ansonia from Malaysian Borneo have long been suspected to be specifically distinct on the basis of molecular data. We assessed the taxonomic status of these lineages using morphological and additional genetic data. In mtDNA phylogeny, each lineage-one from Bario, Kelabit Highlands of Sarawak, the other from Mt. Mulu of Sarawak and the Crocker Range of Sabah-is separated from other congeners by large genetic distances, comparable with those observed between heterospecific species in the genus. These lineages are also morphologically distinguishable from other species, and are considered to represent valid, independently evolving species. We therefore describe them as A. kelabitensis sp. nov. and A. kanak sp. nov.
    Matched MeSH terms: Larva/anatomy & histology
  6. Chrysomya bezziana (Diptera: Calliphoridae) infestation in two Malaysian cats treated with oral lotilaner
    Han HS, Yasmin L
    Vet Dermatol, 2020 Aug;31(4):335-e87.
    PMID: 32323413 DOI: 10.1111/vde.12855
    The most common fly species associated with screwworm myiasis in Southeast Asia is Chrysomya bezziana (Ch. bezziana), the Old-World screwworm. Treatment of screwworm myiasis in cats traditionally has comprised subcutaneous injection of ivermectin or oral administration of nitenpyram, combined with aggressive tissue debridement and larval removal under general anaesthesia. Two cats diagnosed with cutaneous myiasis caused by the larvae of Ch. bezziana were treated with lotilaner. In both cats, a single dose of lotilaner at 6-26 mg/kg, killed all larvae within 24 h, negating the need for general anaesthesia. Both cats were simultaneously infested with Lynxacarus radovskyi (L. radovskyi) which also was eradicated with lotilaner. No adverse reactions were observed and both cats recovered without complications.
    Matched MeSH terms: Larva/drug effects
  7. Fulltext Pro-fibrinolytic potential of the third larval stage of Ascaris suum as a possible mechanism facilitating its migration through the host tissues
    Diosdado A, Simón F, Morchón R, González-Miguel J
    Parasit Vectors, 2020 Apr 20;13(1):203.
    PMID: 32312291 DOI: 10.1186/s13071-020-04067-5
    BACKGROUND: Ascaris roundworms are the parasitic nematodes responsible for causing human and porcine ascariasis. Whereas A. lumbricoides is the most common soil-transmitted helminth infecting humans in the world, A. suum causes important economic losses in the porcine industry. The latter has been proposed as a model for the study of A. lumbricoides since both species are closely related. The third larval stage of these parasites carries out an intriguing and complex hepatopulmonary route through the bloodstream of its hosts. This allows the interaction between larvae and the physiological mechanisms of the hosts circulatory system, such as the fibrinolytic system. Parasite migration has been widely linked to the activation of this system by pathogens that are able to bind plasminogen and enhance plasmin generation. Therefore, the aim of this study was to examine the interaction between the infective third larval stage of A. suum and the host fibrinolytic system as a model of the host-Ascaris spp. relationships.

    METHODS: Infective larvae were obtained after incubating and hatching fertile eggs of A. suum in order to extract their cuticle and excretory/secretory antigens. The ability of both extracts to bind and activate plasminogen, as well as promote plasmin generation were assayed by ELISA and western blot. The location of plasminogen binding on the larval surface was revealed by immunofluorescence. The plasminogen-binding proteins from both antigenic extracts were revealed by two-dimensional electrophoresis and plasminogen-ligand blotting, and identified by mass spectrometry.

    RESULTS: Cuticle and excretory/secretory antigens from infective larvae of A. suum were able to bind plasminogen and promote plasmin generation in the presence of plasminogen activators. Plasminogen binding was located on the larval surface. Twelve plasminogen-binding proteins were identified in both antigenic extracts.

    CONCLUSIONS: To the best of our knowledge, the present results showed for the first time, the pro-fibrinolytic potential of infective larvae of Ascaris spp., which suggests a novel parasite survival mechanism by facilitating the migration through host tissues.

    Matched MeSH terms: Larva/physiology
  8. Fulltext Detection of dengue virus from field Aedes aegypti and Aedes albopictus adults and larvae
    Ahmad R, Ismail A, Saat Z, Lim LH
    Southeast Asian J Trop Med Public Health, 1997 Mar;28(1):138-42.
    PMID: 9322296
    Mosquito adults and larvae were collected from dengue high risk areas and transported to the laboratory for identification. Identified mosquitos were pooled according to the species, date and locality and stored at -70 degrees C. A total of 1,385 pools of Aedes albopictus and 267 pools of Ae. Aegypti were collected from major towns in 12 states in Peninsular Malaysia. Virus isolation was carried out using cell culture (C6/36 clone) of Ae. albopictus and detection of dengue virus by the peroxidase anti-peroxidase staining. All positive isolations were further re-confirmed by the reverse transcriptase-polymerase chain reaction (RT-PCR). Most of the pools were negative with PAP staining and RT-PCR. However, 11 mosquito pools were positive with PAP staining. On the other hand, samples from Terengganu, Pulau Pinang and Johor were positive using both methods.
    Matched MeSH terms: Larva/virology
  9. Toxicity of phenol on Macrobrachium rosenbergii (de Man) eggs, larvae, and post-larvae
    Law AT, Yeo ME
    Bull Environ Contam Toxicol, 1997 Mar;58(3):469-74.
    PMID: 9008059
    Matched MeSH terms: Larva/drug effects
  10. Species composition of adult Anopheles populations and their breeding habitats in Hulu Perak district, Peninsular Malaysia
    Rahman WA, Adanan CR, Abu Hassan A
    Southeast Asian J Trop Med Public Health, 2002 Sep;33(3):547-50.
    PMID: 12693589
    Using the cow-baited trap (CBT) method, 1,845 Anopheles mosquitos, comprising 14 species, were caught in malaria-endemic area of Hulu Perak district, Peninsular Malaysia. The two dominant species were An. barbirostris (18.59%) and An. aconitus (18.86%). Anopheles maculatus, the main malaria vector, constituted 9.11% of the total number of mosquitos sampled. Three hundred and seventy-seven Anopheles larvae, comprising 8 species, were sampled using the North Carolina Biological Station dipper. Anopheles barbirostris larvae amounted to 64.69% of the total number of larvae; An. aconitus accounted for 10.65% of larvae. Seven habitats were identified as breeding places of Anopheles. Most species were found to breed in paddies, fishponds, and rivers. Other less popular habitats were temporary pools, mountain streams, and spring wells.
    Matched MeSH terms: Larva/physiology
  11. Fulltext Glutathion S-transferase activity and DDT-susceptibility of Malaysian mosquitos
    Lee HL, Chong WL
    Southeast Asian J Trop Med Public Health, 1995 Mar;26(1):164-7.
    PMID: 8525405
    Comparative DDT-susceptibility status and glutathion s-transferase (GST) activity of Malaysian Anopheles maculatus, Culex quinquefasciatus and Aedes aegypti was investigated to ascertain the role of this enzyme in DDT resistance. The standardised WHO dose-mortality bioassay tests were used to determine DDT susceptibility in these mosquitos, whilst GST microassay (Brogdon and Barber, 1990) was conducted to measure the activity of this enzyme in mosquito homogenate. It appeared that DDT susceptibility status of Malaysian mosquitos was not correlated with GST activity.
    Matched MeSH terms: Larva/drug effects
  12. Fulltext Detection and serotyping of dengue viruses by PCR: a simple, rapid method for the isolation of viral RNA from infected mosquito larvae
    Chan SY, Kautner I, Lam SK
    Southeast Asian J Trop Med Public Health, 1994 Jun;25(2):258-61.
    PMID: 7855637
    Dengue viruses pose a considerable global public health problem with an estimated 100 million cases of illness every year. This illustrates the need for rapid and reliable diagnostic methods for proper patient management and disease control. Currently, laboratory diagnosis depends on serology or virus isolation, with both methods having certain drawbacks. Alternatively, reverse transcription and polymerase chain reaction (RT-PCR) offers the potential for the rapid, highly sensitive and specific detection of dengue viruses. Since we occasionally encounter the problem of insufficient amounts of patient serum for the direct detection of dengue viruses, a method was developed for the extraction of viral RNA after biological amplification in mosquito larvae. Using this method, 15 of 19 clinical samples tested were correctly identified using RT-PCR.
    Matched MeSH terms: Larva/virology
  13. Clostridium bifermentans serovar malaysia: characterization of putative mosquito larvicidal proteins
    Nicolas L, Charles JF, de Barjac H
    FEMS Microbiol Lett, 1993 Oct 01;113(1):23-8.
    PMID: 8243978
    The toxicity of Clostridium bifermentans serovar malaysia to mosquito larvae is due to protein toxins, belonging to a novel class of insecticidal toxins. Toxic extracts contains three major proteins of 66, 18 and 16 kDa. The 18-kDa and 16-kDa proteins are probably involved in toxicity. They are synthesised during sporulation, concomitant with activity. They are absent from non-toxic strains of C. bifermentans and are present at very low levels in non-toxic C. bifermentans serovar malaysia cultures produced at 42 degrees C. The 66-kDa protein is present throughout the growth phases of C. bifermentans serovar malaysia, and an immunologically related 66-kDa protein is present in non-toxic C. bifermentans strains.
    Matched MeSH terms: Larva/drug effects
  14. Insecticide toxicity, glutathione transferases and carboxylesterase activities in the larva of the Aedes mosquito
    Shamaan NA, Hamidah R, Jeffries J, Hashim AJ, Wan Ngah WZ
    Comp Biochem Physiol C Comp Pharmacol Toxicol, 1993 Jan;104(1):107-10.
    PMID: 8097444
    1. Toxicity evaluations of DDT, lindane, abate and carbaryl were carried out in the larvae of two wild Aedes aegypti strains from Kuala Lumpur and Klang. The Kuala Lumpur strain was more susceptible to the insecticides than the Klang strain. 2. The lethal toxicity time was also determined. The insecticides were found to take a longer time to exert their effect in the Klang strain as compared to the Kuala Lumpur strain. 3. Carboxylesterase activity was determined to be higher in the Kuala Lumpur strain, but glutathione transferase activities were higher in the Klang strain.
    Matched MeSH terms: Larva/enzymology
  15. p-O-geranylcoumaric acid from Melicope lunu-ankenda
    Ramli I, Kamarulzaman NH, Shaari K, Ee GC
    Nat Prod Res, 2004 Aug;18(4):289-94.
    PMID: 15214478
    Leaf extracts of Melicope lunu-ankenda were chemically studied and found to contain mixtures of hydrocarbons and squalene, fatty acids and esters. A geranylated coumaric acid was isolated as the major compound. The crude dichloromethane and methanol extracts of the leaves were found to be strongly larvicidal with LC50 values below 20 microg mL(-1). This is a first isolation of p-O-geranylcoumaric acid from this plant.
    Matched MeSH terms: Larva/drug effects
  16. The establishment and development of Trichostrongylus colubriformis in goats
    Rahman WA, Collins GH
    Vet Parasitol, 1990 Mar;35(3):195-200.
    PMID: 2343537
    Twelve goats were inoculated with 20,000 infective larvae of Trichostrongylus colubriformis and two were killed on each of Days 4, 7, 11, 14, 18 and 21 after inoculation (DAI). The number of worms that established, and the site of development were recorded. Most of the worms established within the first 3 m of the small intestine. There was little relocation or loss of nematodes after establishment. The worms started to migrate from the mucosa to the lumen 11 days after infection. At 4 DAI, 63% of the worms were still at the late L3 stage; the remainder of the worm population had completed the third moult to the L4 stage. The population at 11 DAI comprised largely young adults. When 21 DAI was reached, about 57% of the female worms had eggs in their uteri.
    Matched MeSH terms: Larva/growth & development
  17. The establishment and development of Haemonchus contortus in goats
    Rahman WA, Collins GH
    Vet Parasitol, 1990 Mar;35(3):189-93.
    PMID: 2343536
    Twelve goats were inoculated with 40,000 third-stage Haemonchus contortus larvae and two were killed on each of Days 4, 7, 11, 14, 18 and 21 after inoculation (DAI). The number of worms that established, and the site of development were recorded. More worms established in the fundic, than in the middle or pyloric thirds of the abomasum. Early development occurred within the mucosa; emergence into the lumen started between 7 and 11 days after infection. By 4 DAI, all worms had completed the third moult to the L4 stage. At 11 DAI the majority of the worms were adults. A mean of 13.2% of the female worms had eggs in their uteri at 18 DAI; by 21 DAI more than half of the female worms had eggs in their uteri. The development of H. contortus was essentially similar to that described in sheep.
    Matched MeSH terms: Larva/growth & development
  18. Antibodies in human sera reacting with an insect pathogenic virus
    MacCallum F, Brown G, Tinsley T
    Intervirology, 1979;11(4):234-7.
    PMID: 107144
    Precipitating antibodies to an insect pathogenic RNA virus of Darna trima from East Malaysia have been found in a small percentage of human sera from several different groups of persons in West Malaysia and the United Kingdom. No associated illness was identified. The results suggest that an antigenically related virus or viruses are present in the environment that may be associated with symptomless or inapparent infections in man.
    Matched MeSH terms: Larva/microbiology
  19. Laboratory and field tests of temephos (AbateR) on mosquito larvae and non-target organisms in rice fields in Malaysia
    Yap HH, Lau BL, Leong YP
    Southeast Asian J Trop Med Public Health, 1982 Dec;13(4):646-53.
    PMID: 6189198
    The toxic effects of Abate (temephos) on mosquito larvae and non-target organisms were studied in the rice-field and in the laboratory. In the laboratory tests, Culex tritaeniorhychus larvae and cladoceran zooplanktons (predominantly Diaphanosoma and Moinodaphnia species) were found to be highly susceptible to Abate with LC50 values of 0.27 and less than 0.10 parts per billion respectively. Other non-target species in decreasing degree of susceptibility to Abate were copepods (Tropodiaptomus spp.), Aplocheilus panchax and Tubifex worms. In field study, Abate at concentrations 60, 100 and 200 gm hectare-1 is effective in maintaining the rice-fields free of Anopheles and Culex mosquitoes for at least 2 days. No mortality was observed for Aplocheilus panchax and Tubifex worms at the above concentrations; nevertheless, populations of cladoceran zooplanktons and copepods were reduced up to seven days posttreatment.
    Matched MeSH terms: Larva/drug effects
  20. Breeding-site productivity of the swamp forest mosquitoes Mansonia bonneae and Ma. dives in Sarawak, east Malaysia
    Chang MS, Jute N, Lah J
    Med Vet Entomol, 1988 Jan;2(1):19-28.
    PMID: 2908782
    Studies on larval population densities and adult emergence rates of the Brugian filariasis vectors Mansonia bonneae Edwards and Ma. dives Schiner were conducted in freshwater swamp forest bordering the Sadong River, Serian District, Sarawak, East Malaysia, during 1984-85. Three species of aquatic host-plants in the Family Araceae were identified as supporting immature stages of the Ma. bonneae/dives complex. Proportions of positive plants were 4.7%, 6.5% and 3.4% with 6.4 +/- 2.6, 7.3 +/- 2.8 and 10.1 +/- 1.1 larvae per positive plant, respectively, for the plant species Homalomena cordata Schott, H. rostrata Griffiths and Hydrostemma motleyi (Hook. f.) Mabberley. These data indicate no significant preferences between the three types of host-plant. Detailed monitoring of the host-plant H. cordata revealed no significant monthly fluctuations in larval density per plant nor the proportion of positive plants. 11.6% of larvae were Ma. dives and 88.4% were Ma. bonneae. Mean daily yields of Ma. bonneae/dives adults per square metre of H. cordata vegetated water surface were 0.45 males plus 0.57 females during the wet season (December-February) compared with 0.2 males plus 0.31 females during the dry season (June-August). Thus output of adults per plant was approximately halved, and suitable breeding areas were further reduced, during the dry season. By extrapolation from these rates, a crude mean estimate for productivity of Ma. bonneae/dives females is 1.6 million per hectare per annum in swamp forest habitats vegetated with any of the host-plants studied.
    Matched MeSH terms: Larva/growth & development
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