Displaying publications 21 - 40 of 101 in total

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  1. Fulltext Diversity and biogeography of land snails (Mollusca, Gastropoda) in the limestone hills of Perak, Peninsular Malaysia
    Foon JK, Clements GR, Liew TS
    Zookeys, 2017.
    PMID: 28769723 DOI: 10.3897/zookeys.682.12999
    Limestone hills are now gaining global conservation attention as hotspots for short-range endemic species. Levels of land snail endemism can be high at limestone hills, especially at hill clusters that are geographically isolated. In the State of Perak, Peninsular Malaysia, limestone hills have been opportunistically surveyed for land snails in the past, but the majority have yet to be surveyed. To address this knowledge gap, we systematically surveyed the terrestrial malacofauna of 12 limestone hills that, based on our opinion, are a representation of the limestone land snail assemblages within the State. Our inventory yielded high sampling completeness (>85%). We found 122 species of land snails, of which 34 species were unique to one of the surveyed hills. We identified 30 species that are potentially new to science. The number of land snail species recorded at each hill ranged between 39 and 63 species. Four of the sampled limestone hills namely, Prk 01 G. Tempurung, Prk 55 G. Pondok, Prk 47 Kanthan, and Prk 64 Bt Kepala Gajah, have high levels of species richness and unique species, representing 91% of the total species recorded in this study. We identified two clusters of limestone hills in central Perak with distinct differences in land snail species composition - a northern hill cluster on elevated granite bedrock and southern hill cluster in a low-lying valley surrounded by alluvial soils. As limestone hills continue to be quarried to meet the cement demand, the four identified limestone hills, along with other hills from the two clusters, warrant urgent conservation attention in order to maintain high species diversity within Perak's terrestrial malacofauna.
    Matched MeSH terms: Snails
  2. Epidemiology and control of schistosomiasis in Southeast Asia
    Harinasuta C
    Southeast Asian J. Trop. Med. Public Health, 1984 Dec;15(4):431-8.
    PMID: 6535256
    Schistosomiasis in Southeast Asia, caused by Schistosoma japonicum, Schistosoma mekongi and Schistosoma japonicum-like, have been reported from six different countries. The S. japonicum infections are highly prevalent in the Philippines with Oncomelania hupensis quadrasi as the vector snail, and in localized areas in Indonesia with O.h. lindoensis as the snail vector. The S. mekongi infections are recent discovery in the Lower Mekong Basin in Laos and Kampuchea, with Tricula aperta as the vector snail. The S. japonicum-like infections are found as isolated cases diagnosed by the finding of S. japonicum-like eggs in the faeces, rectal biopsy, tissue biopsy or at necropsy in Thailand and Malaysia. The control measures of schistosomiasis have been implemented in the Philippines and Indonesia, while further research studies are being conducted in Thailand and Malaysia.
    Matched MeSH terms: Snails/parasitology
  3. Fulltext Exploring molecular variation in Schistosoma japonicum in China
    Young ND, Chan KG, Korhonen PK, Min Chong T, Ee R, Mohandas N, et al.
    Sci Rep, 2015;5:17345.
    PMID: 26621075 DOI: 10.1038/srep17345
    Schistosomiasis is a neglected tropical disease that affects more than 200 million people worldwide. The main disease-causing agents, Schistosoma japonicum, S. mansoni and S. haematobium, are blood flukes that have complex life cycles involving a snail intermediate host. In Asia, S. japonicum causes hepatointestinal disease (schistosomiasis japonica) and is challenging to control due to a broad distribution of its snail hosts and range of animal reservoir hosts. In China, extensive efforts have been underway to control this parasite, but genetic variability in S. japonicum populations could represent an obstacle to eliminating schistosomiasis japonica. Although a draft genome sequence is available for S. japonicum, there has been no previous study of molecular variation in this parasite on a genome-wide scale. In this study, we conducted the first deep genomic exploration of seven S. japonicum populations from mainland China, constructed phylogenies using mitochondrial and nuclear genomic data sets, and established considerable variation between some of the populations in genes inferred to be linked to key cellular processes and/or pathogen-host interactions. Based on the findings from this study, we propose that verifying intraspecific conservation in vaccine or drug target candidates is an important first step toward developing effective vaccines and chemotherapies against schistosomiasis.
    Matched MeSH terms: Snails
  4. Features of intertidal bioerosion and bioconstruction on limestone coasts of Langkawi Islands, Malaysia
    Miklós Kázmér, Mohd Shafeea Leman & Kamal Roslan Mohamed, Che Aziz Ali, Danko Taboroši
    Sains Malaysiana, 2015;44:921-929.
    The purpose of this paper was to provide a practical guide assisting field workers in identification and interpretation of frequently occurring bioerosional textures created in limestone by intertidal organisms along the coasts of Langkawi Islands, Malaysia. The discussion follows the textural succession from the supratidal down to the lower intertidal zone. Traces left by lichens, boring sponges, molluscs (littorinid snails, the chiton Acanthopleura, the bivalve Lithophaga) and the echinoid Echinometra are illustrated. Products of bioconstructing organisms, specifically oysters and barnacle are also described. Ecological tolerance of each group is given.
    Matched MeSH terms: Snails
  5. Freshwater snail consumption and angiostrongyliasis in Malaya
    Liat LB, Fong YL, Krishnansamy M, Ramachandran P, Mansor S
    Trop Geogr Med, 1978 Jun;30(2):241-6.
    PMID: 726037
    A survey of the freshwater snails, Pila scutata and Bellamyia ingallsiana, as food consumed by the local population was carried out in Peninsular Malaysia. Of these two species the first is preferred; the sizes favoured are between 25--40 mm. Pila snails were found to be consumed by the three communities, viz. Malay, Chinese and Indian, in different ways. The various methods of preparing the snails for consumption are described. P. scutata is an intermediate host of the rat-lung worm, Angiostrongylus malaysiensis. As this worm presumably is the causative agent of human eosinophilic meningoencephalitis, the eating habits of the three races in consuming the snail in relation to the epidemiology of the disease was also discussed.
    Matched MeSH terms: Snails*
  6. Further field trial to control Schistosoma spindale by trematode antagonism
    Joe LK, Hoa KE, Kong OC
    Southeast Asian J. Trop. Med. Public Health, 1971 Jun;2(2):237-43.
    PMID: 5167566
    Matched MeSH terms: Snails
  7. Gill and digestive caecum of telescopium telescopium as biomonitors of pb bioavailability and contamination by pb in the tropical intertidal area
    Yap C, Noorhaidah A
    Sains Malaysiana, 2011;40:1075-1085.
    In this paper we investigated the concentrations of Pb in seven different soft tissues (foot, cephalic tentacles, mantle muscle, gill, digestive caecum and remaining soft tissues) of 17 geographical populations of Telescopium telescopium collected from the intertidal area of Peninsular Malaysia. Two points can be presented based on the present study. First, as expected, different concentrations of Pb were found in the different soft tissues, indicating different mechanisms of bioaccumulation and regulations of Pb in these different tissues. By comparing the Pb concentrations in the similar tissues, spatial variation of Pb was found in the different sampling sites although there is no consistent pattern of Pb contamination in these sampling sites. Second, based on the correlation coefficients and multiple linear stepwise regression analysis between Pb concentrations in the different soft tissues and Pb concentrations in geochemical factions in the surface sediments, it is found that gill and digestive caecum can truly reflect Pb contamination and Pb bioavailabilities in the tropical intertidal mudflats. To our knowledge, this is the most comprehensive study on Pb in the different soft tissues of T. telescopium, in relation to the habitat sediments of the snails.
    Matched MeSH terms: Snails
  8. Gross mismatch between thermal tolerances and environmental temperatures in a tropical freshwater snail: climate warming and evolutionary implications
    Polgar G, Khang TF, Chua T, Marshall DJ
    J Therm Biol, 2015 Jan;47:99-108.
    PMID: 25526660 DOI: 10.1016/j.jtherbio.2014.11.009
    The relationship between acute thermal tolerance and habitat temperature in ectotherm animals informs about their thermal adaptation and is used to assess thermal safety margins and sensitivity to climate warming. We studied this relationship in an equatorial freshwater snail (Clea nigricans), belonging to a predominantly marine gastropod lineage (Neogastropoda, Buccinidae). We found that tolerance of heating and cooling exceeded average daily maximum and minimum temperatures, by roughly 20°C in each case. Because habitat temperature is generally assumed to be the main selective factor acting on the fundamental thermal niche, the discordance between thermal tolerance and environmental temperature implies trait conservation following 'in situ' environmental change, or following novel colonisation of a thermally less-variable habitat. Whereas heat tolerance could relate to an historical association with the thermally variable and extreme marine intertidal fringe zone, cold tolerance could associate with either an ancestral life at higher latitudes, or represent adaptation to cooler, higher-altitudinal, tropical lotic systems. The broad upper thermal safety margin (difference between heat tolerance and maximum environmental temperature) observed in this snail is grossly incompatible with the very narrow safety margins typically found in most terrestrial tropical ectotherms (insects and lizards), and hence with the emerging prediction that tropical ectotherms, are especially vulnerable to environmental warming. A more comprehensive understanding of climatic vulnerability of animal ectotherms thus requires greater consideration of taxonomic diversity, ecological transition and evolutionary history.
    Matched MeSH terms: Snails/physiology*
  9. Heavy metals in freshwater snails of Kuala Klawang's rice field, Negeri Sembilan, Malaysia
    Ismail A
    Environ Monit Assess, 1994 Sep;32(3):187-91.
    PMID: 24214132 DOI: 10.1007/BF00546274
    A study of heavy metal contents in freshwater snails from rice fields have been made. The results indicate that the levels of heavy metals, Pb, Cu, Zn and Cd, are low and within the permissible limit of Malaysian Food Regulations. The results can serve as background data for further reference.
    Matched MeSH terms: Snails
  10. High thermal stress responses of Echinolittorina snails at their range edge predict population vulnerability to future warming
    Han GD, Cartwright SR, Ganmanee M, Chan BKK, Adzis KAA, Hutchinson N, et al.
    Sci Total Environ, 2019 Jan 10;647:763-771.
    PMID: 30092533 DOI: 10.1016/j.scitotenv.2018.08.005
    Populations at the edge of their species' distribution ranges are typically living at the physiological extreme of the environmental conditions they can tolerate. As a species' response to global change is likely to be largely determined by its physiological performance, subsequent changes in environmental conditions can profoundly influence populations at range edges, resulting in range extensions or retractions. To understand the differential physiological performance among populations at their distribution range edge and center, we measured levels of mRNA for heat shock protein 70 (hsp70) as an indicator of temperature sensitivity in two high-shore littorinid snails, Echinolittorina malaccana and E. radiata, between 1°N to 36°N along the NW Pacific coast. These Echinolittorina snails are extremely heat-tolerant and frequently experience environmental temperatures in excess of 55 °C when emersed. It was assumed that animals exhibiting high temperature sensitivity will synthesize higher levels of mRNA, which will thus lead to higher energetic costs for thermal defense. Populations showed significant geographic variation in temperature sensitivity along their range. Snails at the northern range edge of E. malaccana and southern range edge of E. radiata exhibited higher levels of hsp70 expression than individuals collected from populations at the center of their respective ranges. The high levels of hsp70 mRNA in populations at the edge of a species' distribution range may serve as an adaptive response to locally stressful thermal environments, suggesting populations at the edge of their distribution range are potentially more sensitive to future global warming.
    Matched MeSH terms: Snails/physiology*
  11. Host range of Clostridium bifermentans serovar. malaysia, a mosquitocidal anaerobic bacterium
    Thiery I, Hamon S, Gaven B, De Barjac H
    J Am Mosq Control Assoc, 1992 Sep;8(3):272-7.
    PMID: 1357087
    Clostridium bifermentans serovar. malaysia (C.b.m.) is toxic to mosquito larvae. In this study, we quantified its toxicity to the mosquitoes, Aedes aegypti, Ae. albopictus, Ae. caspius, Ae. detritus, Anopheles stephensi, An. gambiae, Culex pipiens and Cx. quinquefasciatus. Anopheles larvae are the most susceptible, followed by Ae. detritus and Ae. caspius, then Culex and other Aedes larvae. According to mosquito species, the LC50 varies from 7 x 10(3) to 1.3 x 10(6) cells/ml. Three concentrations (10(7), 10(6) and 10(5) cells/ml) of C.b.m., Bacillus thuringiensis var. israelensis (B.t.i.) and Bacillus sphaericus were tested on Ae. aegypti, An. stephensi and Cx. pipiens larvae in order to determine the time necessary for each concentration to kill 50 and 90% of the population. Ninety percent of the 3 mosquito populations are killed within 4-15 h by the C.b.m. concentrations. Whatever the concentrations, C.b.m. kills at least 10 times less rapidly than B.t.i. but always quicker than B. sphaericus. Bioassays of C.b.m. bacterial cells or final whole culture were not toxic to Musca domestica and Drosophila melanogaster (Diptera) as well as to Phaedon cochleariae (Coleoptera) and Spodoptera littoralis (Lepidoptera).
    Matched MeSH terms: Snails/microbiology
  12. Host-parasite studies of Angiostrongylus cantonensis (Nematoda, Metastrongylidae) in Malaysian rodents: natural infection of rodents and molluscs in urban and rural areas of central Malaya
    Lim BL, Heyneman D
    Ann Trop Med Parasitol, 1965 Dec;59(4):425-33.
    PMID: 5862610
    Matched MeSH terms: Snails
  13. Identification of major and cross-reactive allergens of local freshwater snail (Pila polita) and the impact of thermal and non-thermal food processing on allergen stability
    Misnan R, Kamarazaman NA, Sockalingam K, Yadzir ZHM, Bakhtiar F, Abdullah N, et al.
    J Sci Food Agric, 2023 Sep;103(12):5819-5830.
    PMID: 37092326 DOI: 10.1002/jsfa.12659
    BACKGROUND: Snail allergy is rare but can be fatal. Pila polita, a freshwater snail, was considered as a popular exotic food, particularly in tropical countries, and consumed in processed forms. Thus, the purpose of this study was to identify the major and cross-reactive allergens of P. polita and to determine the impact of food processing on the allergen stability.

    RESULTS: Sodium dodecyl sulfate-polyacrylamide gel electrophoresis fractionated raw snail extract to approximately 24 protein bands, between 9 and 245 kDa. The prominent band at 33 kDa was detected in all raw and processed snail extracts. Immunoblotting tests of the raw extract demonstrated 19 immunoglobulin E (IgE)-binding proteins, and four of them, at 30, 35, 42 and 49 kDa, were revealed as the major IgE-binding proteins of P. polita. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry identified the 49 and 42 kDa major allergens as actin, whereas the 30 and 35 kDa major allergens were identified as tropomyosin. Immunoblotting revealed that the raw snail had more allergenic proteins than the processed snail. The degree of allergenicity in decreasing order was raw > brine pickled> boiled > roasted > fried > vinegar pickled. The presence of cross-reactivity between P. polita and the shellfish tested was exhibited with either no, complete, or partial inhibitions.

    CONCLUSION: Actin and tropomyosin were identified as the major and cross-reactive allergens of P. polita among local patients with snail allergy. Those major allergens are highly stable to high temperatures, acidic pH, and high salt, which might played a crucial role in snail allergy in Malaysia. © 2023 Society of Chemical Industry.

    Matched MeSH terms: Snails
  14. Impacts of Thermal Treatments on Major and Minor Allergens of Sea Snail, Cerithidea obtusa (Obtuse Horn Shell)
    Misnan R, Salahudin Abd Aziz N, Mohamad Yadzir ZH, Bakhtiar F, Abdullah N, Murad S
    Iran J Allergy Asthma Immunol, 2016 Aug;15(4):309-316.
    PMID: 27921412
    Snail is one of the worst causes of food allergy. Thus, the aim of this study was to identify the major and minor allergens of the local marine snail (Cerithidea obtusa) and subsequently to investigate the impacts of heat treatment on the IgE-binding activity of snail allergens. Proteins from raw and heat-treated snails (boiled, roasted and fried) were extracted and then resolved by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE). Immunoblotting of all extracts were then performed using sera from patients with snail allergy. The results showed that the raw extract contains numerous protein bands between 12 to>250 kDa. Some thermostable proteins, predominantly the 33 and 42 kDa bands, remained detected in all cooked extracts with decreasing intensities from boiled to roasted to fried extracts, while the majority of thermolabile bands denatured after heating. Boiled snail had more protein bands compared to roasted and fried snails. Immunoblotting of raw extract demostrated 19 IgE-binding bands ranging from 15 to 240 kDa. The thermostable bands of 33 and 42 kDa and a thermolabile of 30 kDa band were identified as the major allergens of this snail. The cooked extracts yielded less allergenic bands. The boiled extract yielded approximately 14 IgE-binding bands with some smeared bands at high molecular weight regions. The roasted extract had lesser IgE-binding bands and the majority appeared as smears, while the IgE-reactivity in the fried extract was less visible and appeared as weak smears. This study indicated that both raw and cooked snails played a crucial role in snail allergenicity, as this species of snail contains both thermostable and thermolabile major allergens. The degree of snail allergenicity was revealed in the order: raw> boiled > roasted> fried. Thus, the results would facilitate in the development of effective diagnosis and management strategies of snail allergy in this country.
    Matched MeSH terms: Snails*
  15. Infection of single snails with two different trematodes. I. Simultaneous exposure and early development of a schistosome and an echinostome
    Basch PF, Joe LK
    Z Parasitenkd, 1966;27(3):252-9.
    PMID: 5990058
    Matched MeSH terms: Snails*
  16. Infection of single snails with two different trematodes. II. Dual exposures to a schistosome and an Echinostome at staggered intervals
    Basch PF, Joe LK
    Z Parasitenkd, 1966;27(3):260-70.
    PMID: 5990059
    Matched MeSH terms: Snails
  17. Fulltext Inferring microevolution from museum collections and resampling: lessons learned from Cepaea
    Ożgo M, Liew TS, Webster NB, Schilthuizen M
    PeerJ, 2017;5:e3938.
    PMID: 29093997 DOI: 10.7717/peerj.3938
    Natural history collections are an important and largely untapped source of long-term data on evolutionary changes in wild populations. Here, we utilize three large geo-referenced sets of samples of the common European land-snail Cepaea nemoralis stored in the collection of Naturalis Biodiversity Center in Leiden, the Netherlands. Resampling of these populations allowed us to gain insight into changes occurring over 95, 69, and 50 years. Cepaea nemoralis is polymorphic for the colour and banding of the shell; the mode of inheritance of these patterns is known, and the polymorphism is under both thermal and predatory selection. At two sites the general direction of changes was towards lighter shells (yellow and less heavily banded), which is consistent with predictions based on on-going climatic change. At one site no directional changes were detected. At all sites there were significant shifts in morph frequencies between years, and our study contributes to the recognition that short-term changes in the states of populations often exceed long-term trends. Our interpretation was limited by the few time points available in the studied collections. We therefore stress the need for natural history collections to routinely collect large samples of common species, to allow much more reliable hind-casting of evolutionary responses to environmental change.
    Matched MeSH terms: Snails
  18. Interaction of trematodes by predation within natural double infections in the host snail Indoplanorbis exustus
    Heyneman D, Umathevy T
    Nature, 1968 Jan 20;217(5125):283-5.
    PMID: 5639142
    Matched MeSH terms: Snails*
  19. Fulltext Land snail fauna in Gunung Kuang Limestone Hill, Perak, Malaysia and its conservation implications (Mollusca, Gastropoda)
    Phung CC, Yong YZ, Said MAM, Liew TS
    Zookeys, 2018.
    PMID: 29988791 DOI: 10.3897/zookeys.769.25571
    This paper presents the first land snail species checklist for Gunung Kuang (Kuang Hill), a limestone hill located next to Gunung Kanthan that is recognised as one of the most important limestone hills for its diverse land snail fauna in Kinta Valley. Samplings were carried out at five plots in Gunung Kuang. This survey documented 47 land snail species, in which six species were identified as unique to Gunung Kuang. Approximately half of the land snails from Gunung Kanthan were found in Gunung Kuang. In addition, one of six unique species from Gunung Kanthan was also found in Gunung Kuang. These rich land snail species in Gunung Kuang are similar to other hills in Kinta Valley, but it is relatively lesser than the adjacent Gunung Kanthan. In view of Gunung Kuang's unique land snail species, and its location closest to disturbed Gunung Kanthan, Gunung Kuang should be considered in the conservation management plan for Gunung Kanthan.
    Matched MeSH terms: Helix (Snails); Snails
  20. Land snails and slugs of Bau limestone hills, Sarawak (Malaysia, Borneo), with the descriptions of 13 new species
    Marzuki MEB, Liew TS, Mohd-Azlan J
    Zookeys, 2021;1035:1-113.
    PMID: 33958931 DOI: 10.3897/zookeys.1035.60843
    This study presents a list of land snails and slugs found on limestone hills in the District of Bau, the state of Sarawak in Malaysian Borneo. Systematic and random sampling for land snails was conducted at eight limestone outcrops, namely, Gunung Stulang, Padang Pan, Gunung Kapor, Gunung Lobang Angin, Gunung Doya, Gunung Batu, Bukit Sekunyit and Gunung Sebayat. A total of 122 land snail species was documented with photographs of each species. Of the 122 species collected, 13 are new to science, namely, Acmella bauensissp. nov., Japonia bauensissp. nov., Plectostoma margaretchanaesp. nov., Microcystina arabiisp. nov., Microcystina atonisp. nov., Microcystina pariparisp. nov., Microcystina liratasp. nov., Microcystina oswaldbrakenisp. nov., Microcystina kilatsp. nov., Philalanka jambusanensissp. nov., Everettia microrhytidasp. nov., Everettia minutasp. nov., and Paralaoma sarawakensissp. nov.
    Matched MeSH terms: Snails
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