Displaying publications 81 - 100 of 660 in total

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  1. Fulltext Endemism and diversity of small mammals along two neighboring Bornean mountains
    Camacho-Sanchez M, Hawkins MTR, Tuh Yit Yu F, Maldonado JE, Leonard JA
    PeerJ, 2019;7:e7858.
    PMID: 31608182 DOI: 10.7717/peerj.7858
    Mountains offer replicated units with large biotic and abiotic gradients in a reduced spatial scale. This transforms them into well-suited scenarios to evaluate biogeographic theories. Mountain biogeography is a hot topic of research and many theories have been proposed to describe the changes in biodiversity with elevation. Geometric constraints, which predict the highest diversity to occur in mid-elevations, have been a focal part of this discussion. Despite this, there is no general theory to explain these patterns, probably because of the interaction among different predictors with the local effects of historical factors. We characterize the diversity of small non-volant mammals across the elevational gradient on Mount (Mt.) Kinabalu (4,095 m) and Mt. Tambuyukon (2,579 m), two neighboring mountains in Borneo, Malaysia. We documented a decrease in species richness with elevation which deviates from expectations of the geometric constraints and suggests that spatial factors (e.g., larger diversity in larger areas) are important. The lowland small mammal community was replaced in higher elevations (from above ~1,900 m) with montane communities consisting mainly of high elevation Borneo endemics. The positive correlation we find between elevation and endemism is concordant with a hypothesis that predicts higher endemism with topographical isolation. This supports lineage history and geographic history could be important drivers of species diversity in this region.
    Matched MeSH terms: Borneo
  2. A taxonomic reappraisal of the Smooth Slug Snake Asthenodipsas laevis (Boie, 1827) (Squamata: Pareidae) in Borneo with the description of two new species
    Quah ESH, Grismer LL, Lim KKP, Anuar MSS, Imbun AY
    Zootaxa, 2019 Jul 25;4646(3):zootaxa.4646.3.4.
    PMID: 31717003 DOI: 10.11646/zootaxa.4646.3.4
    A review of the taxonomic status of the Smooth Slug Snake (Asthenodipsas laevis) in Borneo resulted in the discovery of two previously unrecognised species from the highlands of Sabah, East Malaysia. Asthenodipsas jamilinaisi sp. nov. and A. stuebingi sp. nov. are presumed to be closely related to A. laevis based on similarities in pholidosis and patterning but can be separated from A. laevis by their dorsal scale rows of 15/15/15 vs 15/15/13 and the presence of a sharp vertebral keel. Asthenodipsas jamilinaisi sp. nov. can be further differentiated from A. stuebingi sp. nov. by the greatly enlarged size of the vertebral scales, higher number of ventrals in males (173-175 vs 165), higher number of subcaudals (53 vs 35-47) and colour pattern (dark overall with indistinct bands vs lighter head and body with clear, distinct bands and a dark neck patch). The discovery highlights the need for more careful examination of much of the herpetofauna of Borneo that still remains underestimated and understudied. There is an urgent need for continued surveys into its diversity and the collection of genetic material for integrated taxonomic revisions.
    Matched MeSH terms: Borneo
  3. A new skink of the genus Subdoluseps (Hardwicke amp; Gray, 1828) from Peninsular Malaysia
    Grismer LL, Dzukafly Z, Muin MA, Quah ESH, Karin BR, Anuar S, et al.
    Zootaxa, 2019 May 23;4609(2):zootaxa.4609.2.10.
    PMID: 31717113 DOI: 10.11646/zootaxa.4609.2.10
    An integrative taxonomic analysis of Subdoluseps herberti from southern Thailand and Peninsular Malaysia and S. samajaya from Sarawak, East Malaysia (Borneo) recovers the former as paraphyletic with respect to the latter. The analyses recover the three southernmost populations of S. herberti in Peninsular Malaysia as conspecific and the sister lineage of S. samajaya, whereas S. herberti from Thailand and northern Peninsular Malaysia constitute the sister species to S. samajaya plus the southern three Peninsular Malaysian populations. As such, the southern populations are described herein as S. malayana sp. nov. and all three species are referred to as the S. herberti group. Clade boundaries and breaks within this group on the Thai-Malay Peninsula occurring at the Isthmus of Kra, across the Kangar-Pattani line, and between the Thai-Malay Peninsula and Borneo are consistent with phylogeographic patterns of other Sundaic taxa. The discovery of S. malayana sp. nov. continues to underscore the fact that, despite the well-studied nature of the lizard fauna of Peninsular Malaysia, much of it still remains unrealized and for conservation efforts to move forward, field research followed by expeditiously revised taxonomies must continue.
    Matched MeSH terms: Borneo
  4. A distinctive new species of flowerpecker (Passeriformes: Dicaeidae) from Borneo
    Saucier JR, Milensky CM, Caraballo-Ortiz MA, Ragai R, Dahlan NF, Edwards DP
    Zootaxa, 2019 Oct 17;4686(4):zootaxa.4686.4.1.
    PMID: 31719467 DOI: 10.11646/zootaxa.4686.4.1
    The enigmatic 'Spectacled Flowerpecker'-a probable new bird species from the island of Borneo-was first sighted in the Danum Valley of Sabah, Malaysia in 2009. However, the absence of a holotype specimen has prevented its formal scientific description. Since then only a handful of reports from widely disparate localities across the island have emerged, all from lowland sites and often in close association with fruiting mistletoe. Here, we report the long-awaited capture of a specimen of this putative new species and confirm its morphological and molecular distinctiveness as a novel species in the genus Dicaeum.
    Matched MeSH terms: Borneo
  5. Ciri-ciri panggilan katak Borneo (genus: Hylarana) daripada populasi Sarawak, Malaysia
    Ramlah Zainudin, Badrul Munir Mohd Zain, Shukor Mohd Nor, Norhayati Ahmad, Mustafa Abdul Rahman, Inger. RF
    Sains Malaysiana, 2009;38.
    Rakaman panggilan katak Borneo daripada genus Hylarana telah dijalankan di tujuh lokasi kajian di Sarawak, Malaysia. Sebanyak 12 individu daripada lima spesies katak Borneo telah berjaya dirakam dan dianalisis. Daripada 38 pembolehubah panggilan, hanya 27 daripadanya dapat menerangkan ciri-ciri panggilan daripada katak Hylarana Borneo. Saiz katak jantan mempengaruhi secara signifikan tenaga panggilan antara 90:50% amplitud puncak, tempoh nadi di antara 50%, nisbah tempoh panggilan untuk mencapai setengah modulasi frekuensi dan kadar ulangan not. Saiz katak Hylarana Borneo sedikit mempengaruhi frekuensi asas dan dominan panggilan. Di samping itu, taburan pembolehubah panggilan katak dan dendogram Euclid menyokong identiti taksonomi bagi setiap spesies katak Borneo Hylarana.
    Matched MeSH terms: Borneo
  6. The influence of logging on vertebrate responses to mast fruiting
    Granados A, Bernard H, Brodie JF
    J Anim Ecol, 2019 06;88(6):892-902.
    PMID: 30895613 DOI: 10.1111/1365-2656.12983
    Periods of extreme food abundance, such as irregular masting events, can dramatically affect animal populations and communities, but the extent to which anthropogenic disturbances alter animal responses to mast events is not clear. In South-East Asia, dipterocarp trees reproduce in mast fruiting events every 2-10 years in some of the largest masting events on the planet. These trees, however, are targeted for selective logging, reducing the intensity of fruit production and potentially affecting multiple trophic levels. Moreover, animal responses to resource pulse events have largely been studied in systems where the major mast consumers have been extirpated. We sought to evaluate the influence of human-induced habitat disturbance on animal responses to masting in a system where key mast consumers remain extant. We used motion-triggered camera traps to quantify terrestrial mammal and bird occurrences in Sabah, Malaysian Borneo, relative to variation in fruit biomass from 69 plant families during a major (2014) and minor (2015) masting event and a non-mast year (2013), in both logged and unlogged forests. Bearded pigs (Sus barbatus) showed the clearest responses to masting and occurrence rates were highest in unlogged forest in the year following the major mast, suggesting that the pulse in fruit availability increased immigration or reproduction. We also detected local-scale spatial tracking of dipterocarp fruits in bearded pigs in unlogged forest, while this was equivocal in other species. In contrast, pigs and other vertebrate taxa in our study showed limited response to spatial or temporal variation in fruit availability in logged forest. Our findings suggest that vertebrates, namely bearded pigs, may respond to masting via movement and increased reproduction, but that these responses may be attenuated by habitat disturbance.
    Matched MeSH terms: Borneo
  7. The genus Ranatra Fabricius (Heteroptera: Nepidae) in Borneo, with a redescription of Ranatra spinifrons Montandon and the description of a new species
    Tran AD, Poggi R
    Zootaxa, 2019 Feb 12;4555(2):236-246.
    PMID: 30790959 DOI: 10.11646/zootaxa.4555.2.4
    The type of Ranatra spinifrons Montandon, 1910 is redescribed and this taxon is reported from Brunei for the first time. Ranatra heoki sp.n. is described from Sarawak and belongs to the Ranatra gracilis group (sensu Lansbury, 1972). The present paper also provides the first records of the following species for Borneo: Ranatra parmata Mayr, 1865 (from Sabah and Kalimantan); Ranatra rafflesi Tran Polhemus, 2012 (from Sarawak). The latter is also reported from Sumatra for the first time. Ranatra longipes longipes Stål, 1861, previously known from Kalimantan and Sabah, is now reported from Sarawak for the first time. Thus, six species of Ranatra are currently known from Borneo.
    Matched MeSH terms: Borneo
  8. Seasonal variation and mobility of trace metals in the beach sediments of NW Borneo
    Anandkumar A, Nagarajan R, Sellappa Gounder E, Prabakaran K
    Chemosphere, 2022 Jan;287(Pt 1):132069.
    PMID: 34523457 DOI: 10.1016/j.chemosphere.2021.132069
    Miri city has a dynamic coastal environment, mainly influenced by intensive sedimentation from the Baram River and excessive trace metal loading by the Miri River, which are significant environmental concerns. As the mobility, bioavailability, and toxicity of the trace metals in the sediments are largely controlled by their particulate speciation, the modified BCR sequential extraction protocol was applied to determine the particulate speciation of trace metals in the coastal sediments of Miri, to unravel the seasonal geochemical processes responsible for known observations, and to identify possible sources of these trace metals. The granulometric analysis results showed that littoral currents aided by the monsoonal winds have influenced the grain size distribution of the sediments, enabling us to divide the study area into north-east and south-west segments where the geochemical composition are distinct. The Cu (>84%) and Zn (82%) concentrations are predominantly associated with the exchangeable fraction, which is readily bioavailable. Pb and Cd are dominant in non-residual fractions and other metals viz., Fe, Mn, Co, Ni, and Cr are dominant in the residual fraction. Using Pearson's correlation and factor analysis, the major mechanisms controlling the chemistry of the sediments are identified as association of Cu and Zn with fine fraction sediments, sulphide oxidation in the SW segment of the study area, atmospheric fallout of Pb and Cd in the river basins, precipitation of dissolved Fe and Mn supplied from the rivers and remobilization of Mn from the coastal sediments. Based on various pollution indices, it is inferred that the coastal sediments of NW Borneo are contaminated with Cu and Zn, and are largely bioavailable, which can be a threat to the local aquatic organisms, coral reefs, and coastal mangroves.
    Matched MeSH terms: Borneo
  9. On two new species of arboreal crabs from phytotelms in Sarawak, Borneo (Crustacea: Brachyura: Gecarcinucidae: Arachnothelphusa)
    Ng PKL
    Zootaxa, 2021 Aug 06;5016(3):407-418.
    PMID: 34810440 DOI: 10.11646/zootaxa.5016.3.6
    Two new species of the gecarcinucid freshwater crab genus Arachnothelphusa are described from the Malaysian state of Sarawak in Borneo; one from Lanjak-Entimau Wildlife Sanctuary and another from Bako National Park. Arachnothelphusa rimba n. sp. is distinctive in possessing very long legs and a male first gonopod which has a cylindrical proximal part of the terminal segment, with the distal part sharply tapering to an acute tip. Arachnothelphusa bako n. sp. is superficially closest to A. kadamaiana from Sabah, but differs markedly by its narrower epistome, and proportionately shorter third maxillipeds and ambulatory legs.
    Matched MeSH terms: Borneo
  10. Fulltext A preliminary checklist of the freshwater snails of Sabah (Malaysian Borneo) deposited in the BORNEENSIS collection, Universiti Malaysia Sabah
    Ng TH, Dulipat J, Foon JK, Lopes-Lima M, Alexandra Zieritz, Liew TS
    Zookeys, 2017.
    PMID: 28769673 DOI: 10.3897/zookeys.673.12544
    Sabah, a Malaysian state at the north-eastern tip of Borneo, is situated in one of the Earth's biodiversity hotspots yet its freshwater gastropod diversity remains poorly known. An annotated checklist of the freshwater gastropods is presented, based on specimens deposited in the BORNEENSIS collection of the Institute for Tropical Biology and Conservation at Universiti Malaysia Sabah, Malaysia. A KMZ file is also provided, which acts as a repository of digital images and complete collection data of all examined material, so that it can be shared and adapted to facilitate future research.
    Matched MeSH terms: Borneo
  11. Taxonomic revision of the endemic Bornean genera Anexodus Pascoe and Pantilema Aurivillius (Coleoptera, Cerambycidae, Lamiinae)
    Gabriš R, Trnka F, Wahab RA, Kundrata R
    Zookeys, 2017.
    PMID: 28769651 DOI: 10.3897/zookeys.669.12608
    The genera Anexodus Pascoe, 1866 and Pantilema Aurivillius, 1911 (Cerambycidae: Lamiinae: Morimopsini), both endemic to Borneo, are revised. Four species of Anexodus are recognized: A. aquilus Pascoe, 1886 (Malaysia: Sabah), A. sarawakensis Sudre, 1997 (Malaysia: Sarawak), A. syptakovaesp. n. (Malaysia: Sarawak), and A. tufisp. n. (Brunei). Pantilema is a monotypic genus containing P. angustum Aurivillius, 1911 (Malaysia: Sarawak) which is known only from the holotype. For the first time, genital structures are studied in these genera. An identification key for the species of Anexodus is provided and their intraspecific morphological variability and distributions are discussed.
    Matched MeSH terms: Borneo
  12. The Mosses of Crocker Range Park, Malaysian Borneo
    Suleiman M, Masundang DP, Akiyama H
    PhytoKeys, 2017.
    PMID: 29118647 DOI: 10.3897/phytokeys.88.14674
    This paper reports the mosses from Crocker Range Park (CRP) in Sabah, Malaysian Borneo. In total, 293 species, three subspecies and eight varieties belonging to 118 genera and 36 families are reported. This represents about 40% and 47% of the species and infra-specific taxa reported from Borneo and Sabah, respectively. Out of these, six species are new records for Borneo, namely Barbella horridula, Chaetomitrium lancifolium, Distichophyllum leiopogon, Rhaphidostichum luzonense, Rosulabryum capillare and Taxiphyllum taxirameum and 12 species and one variety are new to Sabah. With these additions, the current number of mosses in Sabah and Borneo are 651 and 766, respectively. The largest family of mosses is Calymperaceae with 35 species and one subspecies, followed by Sematophyllaceae with 32 species and two varieties and Pylaisiadelphaceae with 21 species and one variety. In conclusion, CRP has a very high species richness of mosses which is the second highest in Borneo, after Mount Kinabalu.
    Matched MeSH terms: Borneo
  13. Fulltext Out of Borneo: biogeography, phylogeny and divergence date estimates of Artocarpus (Moraceae)
    Williams EW, Gardner EM, Harris R, Chaveerach A, Pereira JT, Zerega NJ
    Ann Bot, 2017 03 01;119(4):611-627.
    PMID: 28073771 DOI: 10.1093/aob/mcw249
    Background and Aims: The breadfruit genus ( Artocarpus , Moraceae) includes valuable underutilized fruit tree crops with a centre of diversity in Southeast Asia. It belongs to the monophyletic tribe Artocarpeae, whose only other members include two small neotropical genera. This study aimed to reconstruct the phylogeny, estimate divergence dates and infer ancestral ranges of Artocarpeae, especially Artocarpus , to better understand spatial and temporal evolutionary relationships and dispersal patterns in a geologically complex region.

    Methods: To investigate the phylogeny and biogeography of Artocarpeae, this study used Bayesian and maximum likelihood approaches to analyze DNA sequences from six plastid and two nuclear regions from 75% of Artocarpus species, both neotropical Artocarpeae genera, and members of all other Moraceae tribes. Six fossil-based calibrations within the Moraceae family were used to infer divergence times. Ancestral areas and estimated dispersal events were also inferred.

    Key Results: Artocarpeae, Artocarpus and four monophyletic Artocarpus subgenera were well supported. A late Cretaceous origin of the Artocarpeae tribe in the Americas is inferred, followed by Eocene radiation of Artocarpus in Asia, with the greatest diversification occurring during the Miocene. Borneo is reconstructed as the ancestral range of Artocarpus , with dozens of independent in situ diversification events inferred there, as well as dispersal events to other regions of Southeast Asia. Dispersal pathways of Artocarpus and its ancestors are proposed.

    Conclusions: Borneo was central in the diversification of the genus Artocarpus and probably served as the centre from which species dispersed and diversified in several directions. The greatest amount of diversification is inferred to have occurred during the Miocene, when sea levels fluctuated and land connections frequently existed between Borneo, mainland Asia, Sumatra and Java. Many species found in these areas have extant overlapping ranges, suggesting that sympatric speciation may have occurred. By contrast, Artocarpus diversity east of Borneo (where many of the islands have no historical connections to the landmasses of the Sunda and Sahul shelves) is unique and probably the product of over water long-distance dispersal events and subsequent diversification in allopatry. This work represents the most comprehensive Artocarpus phylogeny and biogeography study to date and supports Borneo as an evolutionary biodiversity hotspot.

    Matched MeSH terms: Borneo
  14. Fulltext Occurrence and distribution of geochemical elements in Miri estuary, NW Borneo: Evaluating for processes, sources and pollution status
    Suresh Raj PR, Mohan Viswanathan P
    Chemosphere, 2023 Mar;316:137838.
    PMID: 36642142 DOI: 10.1016/j.chemosphere.2023.137838
    In this study, estuarine water samples were collected at diverse hot spots in Miri River Estuary, East Malaysia to appraise the geochemical processes, which controls the river water quality. The collected water samples were analysed for various physicochemical parameters (insitu parameters, nutrients, major ions and trace metals), including stable isotopes (oxygen and hydrogen). Suspended solids are also extracted from the water samples and analysed for trace metals. Standard graphs, Piper plot, Gibbs diagram, water quality indices, geochemical modelling and statistical analysis were used for the data analysis. The acquired water quality data was compared with national and international guidelines for the suitability of water for various purposes. Interpretation of data reveals that the estuarine water quality is deemed unsuitable to be used for both drinking and irrigation purposes. Overall, the elemental concentrations are increasing from downstream to river mouth. Based on pollution indices (HEI and Cd), downstream region shows high vulnerability to metal pollution due to anthropogenic disturbance. Isotope values of river water indicate direct atmospheric precipitation with minimal evaporation. Factor analysis reveals that seawater influx, urban pollution, domestic and agricultural discharges at the downstream region are the main controlling factors to the river water quality. It is also deduced that suspended solids play a vital role in the adsorption and desorption of trace metals in the estuarine water. The outcome of this study provides a comprehensive information on pollution status of Miri estuary, which helps the policy makers to practice sustainable management of this water resource for Miri community.
    Matched MeSH terms: Borneo
  15. Fulltext Assessment on urban lakes along the coastal region of Miri, NW Borneo: implication for hydrochemistry, water quality, and pollution risk
    Nyambar INA, Mohan Viswanathan P
    Environ Sci Pollut Res Int, 2024 Jun;31(29):41306-41328.
    PMID: 36650369 DOI: 10.1007/s11356-023-25172-9
    The main purpose of this study is to assess the urban lake water quality along the coastal region of Miri City, Sarawak, East Malaysia. This study concentrates on the hydrochemical characteristics and the mechanisms controlling the suitability of the lakes for domestic, irrigation, and industrial purposes. A total of 15 lake water samples were collected and analysed for physical parameters, major ions, nutrients, BOD, COD, and heavy metals. The results show that Lakes 6, 7, and 8 commonly exceeded the National Drinking Water Quality Standards (NDWQS) limits, particularly in physical parameters and major ions. The cation dominance was Na+  > Mg2+  > K+  > Ca2+, while the anion dominance was Cl-  > HCO3-  > SO42-. It is inferred that lake 8 was affected by the seawater intrusion through the inlet flow, resulting in an excess concentration of ions present in that lake. The concentrations of heavy metals in these lakes were considerably low, indicating that most of them were from the geogenic source. Most of the lakes were NaCl water type and the main controlling mechanism were weathering and ionic exchange processes, with anthropogenic impacts. Based on the calculated Water Quality Index (WQI) according to the National Water Quality Standards (NWQS), all lakes were suitable for irrigation use (class IV), while most of these lakes fell under the "polluted" index. Apart from that, based on the National Lake Water Quality Standards (NLWQS), all lakes were classified under category D, indicating that the lakes must be kept in good condition. According to the irrigation quality indices, lakes 1, 2, 3, 4, and 5 were the most suitable for irrigation purposes. As for metal pollution indices (HPI and HEI), lakes 1, 2, 3, 4, 5, and 15 were considered safe with low pollution status. From the multivariate statistical analysis, it is deduced that both anthropogenic and geogenic impacts mostly influenced the quality of these lake waters. The outcome of this study will help the policymakers under the national water department in sustainable management of water resources in this region.
    Matched MeSH terms: Borneo
  16. Fulltext Detection of novel coronaviruses from dusky fruit bat (Penthetor lucasi) in Sarawak, Malaysian Borneo
    Habeebur-Rahman SP, Noni V, Khan FAA, Tan CS
    Vet Med Sci, 2023 Nov;9(6):2634-2641.
    PMID: 37658663 DOI: 10.1002/vms3.1251
    BACKGROUND: Sarawak has one of the highest diversity of fruit bats species (family Pteropodidae) in Malaysia, with 19 species described. Most coronavirus (CoV) studies have mainly focused on insectivorous bats, resulting in a lack of information on CoVs present in frugivorous bats. In addition, bat CoV surveillance activities are lacking in Malaysia.

    OBJECTIVES: Our study focuses on determining the presence of bat CoVs in dusky fruit bat (Penthetor lucasi).

    METHODS: Guano samples belonging to P. lucasi were collected from Wind Cave Nature Reserve. The samples were screened for the presence of CoVs using validated hemi-nested consensus RNA-dependent RNA polymerase consensus primers.

    RESULTS: The bat CoV positivity rate was 38.5% (n = 15/39), with the viruses belonging to two subgenera: Alphacoronavirus (α-CoV) and Betacoronavirus (β-CoV). Phylogenetic analysis revealed that CoVs from 14 samples of P. lucasi belong to the genus α-CoV and may represent previously described genetic lineages in insectivorous bats in Wind Cave. However, only one sample of P. lucasi was detected with β-CoV which is closely related to subgenus Nobecovirus, which is commonly seen in frugivorous bats.

    CONCLUSIONS: This study provides the first available data on CoVs circulating in P. lucasi.

    Matched MeSH terms: Borneo
  17. Taxonomy and bioacoustics of scaly crickets (Orthoptera, Mogoplistidae, Mogoplistinae) from Borneo and Singapore
    Tan MK, Japir R, Chung AYC, Wahab RBHA, Robillard T
    Zootaxa, 2022 Nov 24;5213(2):177-189.
    PMID: 37044943 DOI: 10.11646/zootaxa.5213.2.6
    A species of scaly cricket is described here: Ornebius lupus sp. nov. from the mangrove forests in Singapore. Ornebius pullus Ingrisch, 2006 is recorded in eastern Sabah for the first time. The calling songs of Cycloptiloides bimaculatus Tan et al., 2021 and Ornebius pullus from Sabah are described. We also revise the diagnosis of Ectatoderus nigrofasciatus Tan et al., 2021 from Brunei Darussalam.
    Matched MeSH terms: Borneo
  18. Fulltext Serological evaluation of risk factors for exposure to malaria in a pre-elimination setting in Malaysian Borneo
    Byrne I, William T, Chua TH, Patterson C, Hall T, Tan M, et al.
    Sci Rep, 2023 Aug 10;13(1):12998.
    PMID: 37563178 DOI: 10.1038/s41598-023-39670-w
    Malaysia has reported no indigenous cases of P. falciparum and P. vivax for over 3 years. When transmission reaches such low levels, it is important to understand the individuals and locations where exposure risks are high, as they may be at greater risk in the case of a resurgence of transmission. Serology is a useful tool in low transmission settings, providing insight into exposure over longer durations than PCR or RDT. We ran blood samples from a 2015 population-based survey in northern Sabah, Malaysian Borneo on a multiplex bead assay. Using supervised machine learning methods, we characterised recent and historic exposure to Plasmodium falciparum and P. vivax and found recent exposure to P. falciparum to be very low, with exposure to both species increasing with age. We performed a risk-factor assessment on environmental, behavioural, demographic and household factors, and identified forest activity and longer travel times to healthcare as common risk-factors for exposure to P. falciparum and P. vivax. In addition, we used remote-sensing derived data and geostatistical models to assess environmental and spatial associations with exposure. We created predictive maps of exposure to recent P. falciparum in the study area and showed 3 clear foci of exposure. This study provides useful insight into the environmental, spatial and demographic risk factors for P. falciparum and P. vivax at a period of low transmission in Malaysian Borneo. The findings would be valuable in the case of resurgence of human malarias in the region.
    Matched MeSH terms: Borneo
  19. Identification and mechanism determination of the efflux pump subunit amrB gene mutations linked to gentamicin susceptibility in clinical Burkholderia pseudomallei from Malaysian Borneo
    Hussin A, Nathan S, Shahidan MA, Nor Rahim MY, Zainun MY, Khairuddin NAN, et al.
    Mol Genet Genomics, 2024 Feb 21;299(1):12.
    PMID: 38381232 DOI: 10.1007/s00438-024-02105-w
    The bacterium Burkholderia pseudomallei is typically resistant to gentamicin but rare susceptible strains have been isolated in certain regions, such as Thailand and Sarawak, Malaysia. Recently, several amino acid substitutions have been reported in the amrB gene (a subunit of the amrAB-oprA efflux pump gene) that confer gentamicin susceptibility. However, information regarding the mechanism of the substitutions conferring the susceptibility is lacking. To understand the mechanism of amino acid substitution that confers susceptibility, this study identifies the corresponding mutations in clinical gentamicin-susceptible B. pseudomallei isolates from the Malaysian Borneo (n = 46; Sarawak: 5; Sabah: 41). Three phenotypically confirmed gentamicin-susceptible (GENs) strains from Sarawak, Malaysia, were screened for mutations in the amrB gene using gene sequences of gentamicin-resistant (GENr) strains (QEH 56, QEH 57, QEH20, and QEH26) and publicly available sequences (AF072887.1 and BX571965.1) as the comparator. The effect of missense mutations on the stability of the AmrB protein was determined by calculating the average energy change value (ΔΔG). Mutagenesis analysis identified a polymorphism-associated mutation, g.1056 T > G, a possible susceptible-associated in-frame deletion, Delta V412, and a previously confirmed susceptible-associated amino acid substitution, T368R, in each of the three GENs isolates. The contribution of Delta V412 needs further confirmation by experimental mutagenesis analysis. The mechanism by which T368R confers susceptibility, as elucidated by in silico mutagenesis analysis using AmrB-modeled protein structures, is proposed to be due to the location of T368R in a highly conserved region, rather than destabilization of the AmrB protein structure.
    Matched MeSH terms: Borneo
  20. Oxytelus acriculiclypeatus, a New Species of Oxytelus Gravenhorst, 1802 (Coleoptera: Staphylinidae: Oxytelinae) from Borneo
    L L
    Zootaxa, 2024 Feb 23;5415(4):593-597.
    PMID: 38480178 DOI: 10.11646/zootaxa.5415.4.9
    A new species, Oxytelus acriculiclypeatus sp. nov., is described from Malaysia (Borneo: Sabah). The species is similar to O. megaceros Fauvel, 1895, but can be separated based on four male features: a more pointed tip on the anterior margin of the clypeus, a wider central plate on the posterior margin of sternite VIII with a carina that spans the entire width of the posterior margin of medial plate, two sharper and thinner projections on the apical orifice, and the apico-medial hook with a smaller apical tip but without the connecting scape. As a result, a total of 31 confirmed species have been recorded in Southeast Asia hitherto.
    Matched MeSH terms: Borneo
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