Displaying publications 1 - 20 of 445 in total

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  1. Fulltext MACROFUNGI OF PULAU BIDONG
    TSIA MUN KAIK, AQILAH MOHAMMAD
    UMT Journal of Undergraduate Research, 2019;1(2):26-35.
    MyJurnal
    Studies on fungal taxonomy and fungal diversity are crucial for a better understanding of the interactions between fungi and their habitats. To date, there is no published record on macrofungal diversity in Pulau Bidong, Terengganu. Therefore, this study aimed to identify macrofungi species found with their respective substrates and to determine the macrofungal diversity in the island. The study was conducted at two different occasions and comprised of two trails near Universiti Malaysia Terengganu Research Station in Pulau Bidong, Terengganu. Collectionof fresh macrofungi was made and additional data including host information, distinctive features of each fungal sample and several environmental parameters was also recorded. Fresh specimens were later observed and identified before being dried prior to storage. Overall, 65 macrofungal species with 2 unidentified species belonging to 21 families and 34 genera were recorded. Trail A and trail B recorded diversity index of2.67 and 3.14 for Shannon Index while Simpson index recorded 0.90 and 0.94 respectively. The macrofungal diversity was dominated by family Polyporaceae while rare species discovered were from family of Tricholomataceae, Hericiaceae, Stereaceae, Schizophyllaceae, Sclerodermataceae, Dacrymycetaceae, Tremellaceae, Russulaceae and Clavulinaceae. The most common macrofungal substrates was decayed branches while other macrofungal substrates found were decayed trunks and leaves, soil,termite mounds, and living tree. In conclusion, the macrofungal species were randomlydistributed with high diversity in both trails. Therefore, it is recommended that anincrease in sampling trips, sampling efforts and areas covered be provided to increase the number of macrofungal species discovered and accuracy of diversity studies in the future.
    Matched MeSH terms: Trees
  2. Fulltext Accumulation of soil carbon and phosphorus contents of a rehabilitated forest
    Haruna Ahmed O, Aainaa Hasbullah N, Ab Majid NM
    ScientificWorldJournal, 2010 Oct 12;10:1988-95.
    PMID: 20953548 DOI: 10.1100/tsw.2010.196
    The world's tropical rainforests are decreasing at an alarming rate as they are converted to agricultural land, pasture, and plantations. Decreasing tropical forests affect global warming. As a result, afforestation progams have been suggested to mitigate this problem. The objective of this study was to determine the carbon and phosphorus accumulation of a rehabilitated forest of different ages. The size of the study area was 47.5 ha. Soil samples were collected from the 0-, 6-, 12-, and 17-year-old rehabilitated forest. Twenty samples were taken randomly with a soil auger at depths of 0-20 and 20-40 cm. The procedures outlined in the Materials and Methods section were used to analyze the soil samples for pH, total C, organic matter, total P, C/P ratio, yield of humic acid (HA), and cation exchange capacity (CEC). The soil pH decreased significantly with increasing age of forest rehabilitation regardless of depth. Age did not affect CEC of the rehabilitated forest. Soil organic matter (SOM), total C, and total P contents increased with age. However, C/P ratio decreased with time at 0-20 cm. Accumulation of HA with time and soil depth was not consistent. The rehabilitated forest has shown signs of being a C and P sink.
    Matched MeSH terms: Trees/growth & development; Trees/metabolism*
  3. Fulltext The In Vitro and In Vivo Anticancer Properties of Moringa oleifera
    Khor KZ, Lim V, Moses EJ, Abdul Samad N
    Evid Based Complement Alternat Med, 2018;2018:1071243.
    PMID: 30538753 DOI: 10.1155/2018/1071243
    Moringa oleifera, a fast-growing deciduous tree that is widely cultivated in tropical and subtropical regions of the world, is well known for its abundant uses. The tree is a source of food, shelter, and traditional medicine for many people, especially in developing countries. Many studies have been conducted to evaluate the various claims of traditional medicine practitioners that the moringa tree can improve health and treat various diseases. The tree has a high nutritional profile, especially the nutrient rich leaves. Some reports also support the use of parts of the tree to reduce blood sugar and cholesterol levels. These attractive properties have led researchers to look for other novel uses for the moringa tree, especially as a source of anticancer drugs. Researchers have tested extracts from various parts of the moringa tree both in vitro and in vivo on several types of cancers with varying success. This review explores the state of current research on the anticancer properties of M. oleifera.
    Matched MeSH terms: Trees
  4. No evidence of age-related decline in propagated Acer pseudoplatanus and Fraxinus excelsior plants
    Zheng T, Mencuccini M, Abdul-Hamid H
    Physiol Plant, 2023;175(3):e13915.
    PMID: 37087558 DOI: 10.1111/ppl.13915
    Although a substantial body of evidence suggests that large and old trees have reduced metabolic levels, the search for the causes behind this observation has proved elusive. The strong coupling between age and size, commonly encountered in the field, precludes the isolation of the potential causes. We used standard propagation techniques (grafting and air-layering) to decouple the effects of size from those of age in affecting leaf structure, biochemistry and physiology of two broadleaved trees, Acer pseudoplatanus (a diffuse-porous species) and Fraxinus excelsior (a ring-porous species). The first year after establishment of the propagated plants, some of the measurements suggested the presence of age-related declines in metabolism, while other measurements either did not show any difference or suggested variability across treatments not associated with either age or size. During the second year after establishment, only one of the measured properties (specific leaf area) continued to show some evidence of an age-mediated decline (although much reduced compared to the field), whereas, for some properties (particularly for F. excelsior), even the opposite trend of age-related increases was apparent. We concluded that (1) our plants suffered from grafting shock during year 1 and they gradually recovered during year 2; (2) the results over 2 years do not support the statement that age directly mediates ageing in either species but instead suggest that size directly mediates ageing processes; and (3) neither shoots nor roots of A. pseudoplatanus showed any evidence of senescence.
    Matched MeSH terms: Trees/physiology
  5. Fulltext Linkages between Chiropteran diversity and ecosystem services for sustainable fragmented forest conservation
    Fakhrul-Hatta SNN, Nelson BR, Shafie NJ, Zahidin MA, Abdullah MT
    Data Brief, 2018 Dec;21:2089-2094.
    PMID: 30533456 DOI: 10.1016/j.dib.2018.11.058
    This data article informs about Chiropteran diversity, new records, ecosystem services and possible pathogen carriers in fragmented forests (sub-divided by utility corridors, man-made structures, untouched and secondary plantations) within districts Setiu (Setiu Research Station), Hulu Terengganu (Saok and Lasir waterfalls) and Besut (Gunung Tebu Forest Reserve) of state Terengganu, Peninsular Malaysia. These bats were captured using harp traps and mist nets that were set 10 m apart across flyways, streams and less cluttered trees in the 50 m × 50 m transect zones (identified at each site). All animals were distinguished by morphology and gender before their release at the site of capture. The data comprise of five bat family groups Hipposideridae, Megadermatidae, Pteropodidae, Rhinolophidae and Vespertilionidae. It is interesting to note that untouched Saok Waterfalls is home to wide variety of bats listed (68.8%), followed by secondary forests of Gunung Tebu Forest Reserve (24.8%), untouched Lasir Waterfalls (4.8%) and lastly, Setiu Research Station as least favored (1.6%). Chiroptera like Cynopterus brachyotis (n = 23, 37.7%), Hipposideros bicolor (n = 6, 9.8%) and Scotophilus kuhli (n = 6, 9.8%) were most dominant in the checklist whereas Hipposideros armiger, Murina suilla and Scotophilus kuhlii are new data records in the fragmented forests of Terengganu. The data were interpret into Shannon, Simpson, Margalef, Menhinik and Evenness indices to individually or collectively distinguish chiropteran variety in Terengganu State whereas weight-forearm length (W/FA) informs about chiropteran Body Condition Index (-0.25 to 0.25). The function of bats were also identified to distinguish service providers (pollination and forests regeneration) and zoonotic pathogen carriers (in particular to Leptospira bacteria, Nipah virus and Sindbis virus).
    Matched MeSH terms: Trees
  6. Fulltext Diversity of Bats in Contrasting Habitats of Hulu Terengganu Dipterocarp Forest and Setiu Wetland BRIS Forest with a Note on Preliminary Study of Vertical Stratification of Pteropodid Bats
    Pounsin G, Wahab NS, Roslan A, Zahidin MA, Pesiu E, Tamrin NAM, et al.
    Trop Life Sci Res, 2018 Mar;29(1):51-69.
    PMID: 29644015 MyJurnal DOI: 10.21315/tlsr2018.29.1.4
    A study of the bat diversity was conducted in Hulu Terengganu dipterocarp forest and Setiu Wetland Beach Ridges Interspersed with Swales (BRIS) forest in Terengganu, to study the species diversity, composition and stratification of fruit bats from the understorey to the forest canopy. Mist nets were set up at the understorey, sub-canopy and canopy layer while harp traps were set up at the understorey layer. We recorded 170 individuals from six families' compromised 21 species from Hulu Terengganu dipterocarp forests and four species from Setiu Wetland BRIS forests throughout the sampling period. Megaerops ecaudatus and Cynopterus brachyotis were the most dominant species in Hulu Terengganu dipterocarp forest and Setiu Wetland BRIS forests. Our study also recorded two species with new distributional records for the east coast of Peninsular Malaysia, namely, Rhinolophus chiewkweeae and Chaerephon johorensis in Hulu Terengganu dipterocarp forests. Potential factors that might influence the results were in terms of the canopy covers, the structural complexity of canopy, food availability and spatial characteristics. This study was able to increase the knowledge on the species diversity and composition of bats in Hulu Terengganu dipterocarp forest and Setiu Wetland BRIS forest, thus, further aid in the effort of bat conservation in both areas.
    Matched MeSH terms: Trees
  7. Non-volant small mammal data from fragmented forests in Terengganu State
    Khalib NKA, Shafie NJ, Basri HH, Nelson BR, Abdullah MT
    Data Brief, 2018 Dec;21:1514-1520.
    PMID: 30480062 DOI: 10.1016/j.dib.2018.10.061
    This data article is about non-volant small mammal (squirrel, rat and tree shrew) capture from fragmented forest understories within sub-urban areas of Setiu (Peladang Agro Resort and Setiu Wetland Research Station) and inhabited areas of Hulu Terengganu (Saok and Lasir waterfalls) that are situated in Terengganu State, Peninsular Malaysia. Fruits like banana and oil palm were individually placed into each cage before the cages were fastened onto three to five meter height tree branches. The traps were also spatially distributed about ten meters from each other. Under this installation, fifty baited traps were used during the twenty-four nights of sample collection. All animals caught were distinguished by morphology and released at the same location it was caught. The understory data comprise of seven non-volant mammal species from family groups Sciuridae, Muridae and Tupaiidae. Overall, Callosciurus notatus (n = 17, 39%) were dominant in the capture pool from all sites. Comparatively, Sundascriurus tenuis (n = 2, 4%) and Rattus rattus (n = 4, 9.3%) were restricted to Saok Waterfalls and Setiu Wetland. Banana and oil palm fruits did not attract any small mammals during the Lasir Waterfall (Hulu Terengganu) survey. All data were interpret into Shannon, Simpson, Margalef, Menhinik and Evenness indices to individually or collectively distinguish small mammal variety in Terengganu State.
    Matched MeSH terms: Trees
  8. Fulltext Conspectus of flora, fauna and micro-climate data in Tasik Kenyir from Mac 2015-February 2016
    Afiq Ramlee MN, Hussin MF, Roslan A, Rosmidi FH, Pesiu E, Aisyah A Rahim N, et al.
    Data Brief, 2020 Apr;29:105328.
    PMID: 32181296 DOI: 10.1016/j.dib.2020.105328
    This data article presents the diversity of flora and selected fauna in Tasik Kenyir, Malaysia. This man-made lake once suffered huge loss of biodiversity for allowing an earth-dam construction during 1980s. Series of publications on different types of target taxa have been published separately after the post-dam construction. A biodiversity assessment was conducted in Tasik Kenyir from March 2015 until February 2016. The one year assessment were compiled with the previous published data to document and updated the biodiversity checklist in the lake. The data show that Tasik Kenyir is occupied by 113 tree species, 217 butterfly species, 35 bee species, 26 reptile species, 267 aves species and 153 mammal species. The micro-climate data was downloaded from the Malaysian Meteorological Department and analysed in R Studio to highlight the relationship between climate data and biodiversity data.
    Matched MeSH terms: Trees
  9. Fulltext Bats data from fragmented forests in Terengganu State, Malaysia
    Zakaria N, Tarmizi AA, Zuki MAM, Ahmad AB, Mamat MA, Abdullah MT
    Data Brief, 2020 Jun;30:105567.
    PMID: 32382599 DOI: 10.1016/j.dib.2020.105567
    This data article is about bats observed from fragmented forest understories interspaced by agricultural plantations, utility corridors, and man-made structures within rural areas of Setiu (Bukit Kesing Forest Reserve and Ladang Tayor TDM) and Hulu Terengganu (Pengkalan Utama and Sungai Buweh, Kenyir) that are situated in Terengganu state, Peninsular Malaysia. Surveys were conducted from October 2018 until January 2019. These bats were captured using harp traps and mist nets that were set 30 m apart across flyways, streams, rivers and less cluttered trees in the 50 m transect zones (identified at each site). All animals captured were distinguished by morphology and released at the same location it was caught. The data comprise of 15 species of bats from four family groups, namely Hipposideridae, Pteropodidae, Rhinolophidae and Vespertilionidae. The data were interpreted into weight-forearm length (W-FA) to inform about bats Body Condition Index (-0.25 to 0.25).
    Matched MeSH terms: Trees
  10. Fragmented forest in tropical landscape--the case of the state of Selangor, Malaysia
    Abdullah SA
    J Environ Sci (China), 2003 Mar;15(2):267-70.
    PMID: 12765270
    This paper presents the pattern and changes of fragmented forest in relation with changes of total forest cover in the state of Selangor in three decades. In this study, inventoried forest cover maps of Selangor in 1971/1972, 1981/1982 and 1991/1992 produced by the Forestry Department of Peninsular Malaysia were digitized to examine the changes in area and number of fragmented forest. Results showed that in 1971/1972, 16 fragmented forests were identified in Selangor. All fragmented forests were identified as dipterocarp forest. A decade later the number of fragmented forests increased by approximately 44% (23). Of the 23 fragmented forests, two were peat swamp forests whereas the remaining were dipterocarp forests. In 1991/1992 the number of fragmented forests (12) was reduced by 47.8%. Two of the fragmented forests were identified as peat swamp forest, seven dipterocarp forest and the other three was mixed of dipterocarp forests and plantation forests. Fragmentation of both dipterocarp and peat swamp forests occurred profoundly during the period between 1971/1972 and 1981/1982, which consequently increased the number of fragmented forests compared with before the period of 1971/1972 where fragmentation happened only at dipterocarp forests. However, many fragmented forests vanished between the 1981/1982 and 1991/1992 periods.
    Matched MeSH terms: Trees*
  11. Fulltext Evaluation of risk factors for prolonged invasive mechanical ventilation in Paediatric Intensive Care Unit (PICU)
    Ismail, I., Yap, B.W., Abidin, A.S.Z.
    Pertanika Journal of Science & Technology, 2017;25(3):811-824.
    MyJurnal
    Prolonged mechanical ventilation (PMV) is associated with increase in mortality and resource utilisation as well as hospitalisation costs. This study evaluates the risk factors of PMV. A retrospective study was conducted involving 890 paediatric patients comprising 237 neonates, 306 infants, 223 of pre-school age and 124 who are of school going age. The data mining decision trees algorithms and logistic regression was employed to develop predictive models for each age category. The independent variables were classified into four categories, that is, demographic data, admission factors, medical factors and score factors. The dependent variable is the duration of ventilation where it is categorized 0 denoting non-PMV and 1 denoting PMV. The performances of three decision tree models (CHAID, CART and C5.0) and logistic regression were compared to determine the best model. The results indicated that the decision tree outperformed the logistic regression model for all age categories, given its good accuracy rate for testing dataset. Decision trees results identified length of stay and inotropes as significant risk factors in all age categories. PRISM 12 hours and principal diagnosis were identified as significant risk factors for infants.
    Matched MeSH terms: Decision Trees
  12. Activity of extracts and naphthoquinones from Kigelia pinnata against Trypanosoma brucei brucei and Trypanosoma brucei rhodesiense
    Moideen SV, Houghton PJ, Rock P, Croft SL, Aboagye-Nyame F
    Planta Med, 1999 Aug;65(6):536-40.
    PMID: 10483374
    Dichloromethane extracts of the root bark and stem bark of Kigelia pinnata collected from Zimbabwe exhibited antitrypanosomal activity against Trypanosoma brucei brucei in vitro. Activity-guided fractionation led to the isolation of four naphthoquinones from both the root and stem bark of the plant. The compounds were identified as 2-(1-hydroxyethyl)-naphtho[2,3-b]furan-4,9-quinone (1), isopinnatal (2), kigelinol (3), and isokigelinol (4). Subsequently, the compounds were assessed for antitrypanosomal activity against T. brucei brucei and T. brucei rhodesiense bloodstream form trypomastigotes in vitro. Compound 1 with a furanonaphthoquinone structure was found to possess pronounced activity against both parasites with IC50 values of 0.12 and 0.045 microM, respectively, although it was less active than the standard drug pentamidine. Compounds 2, 3, and 4 also exhibited activity against the parasites, although to a lesser extent. The activities of the compounds were further assessed by comparison with the cytotoxic activities obtained against KB cell lines.
    Matched MeSH terms: Trees
  13. Fulltext Plant data visualisation using network graphs
    Mohamad-Matrol AA, Chang SW, Abu A
    PeerJ, 2018;6:e5579.
    PMID: 30186704 DOI: 10.7717/peerj.5579
    Background: The amount of plant data such as taxonomical classification, morphological characteristics, ecological attributes and geological distribution in textual and image forms has increased rapidly due to emerging research and technologies. Therefore, it is crucial for experts as well as the public to discern meaningful relationships from this vast amount of data using appropriate methods. The data are often presented in lengthy texts and tables, which make gaining new insights difficult. The study proposes a visual-based representation to display data to users in a meaningful way. This method emphasises the relationships between different data sets.

    Method: This study involves four main steps which translate text-based results from Extensible Markup Language (XML) serialisation format into graphs. The four steps include: (1) conversion of ontological dataset as graph model data; (2) query from graph model data; (3) transformation of text-based results in XML serialisation format into a graphical form; and (4) display of results to the user via a graphical user interface (GUI). Ontological data for plants and samples of trees and shrubs were used as the dataset to demonstrate how plant-based data could be integrated into the proposed data visualisation.

    Results: A visualisation system named plant visualisation system was developed. This system provides a GUI that enables users to perform the query process, as well as a graphical viewer to display the results of the query in the form of a network graph. The efficiency of the developed visualisation system was measured by performing two types of user evaluations: a usability heuristics evaluation, and a query and visualisation evaluation.

    Discussion: The relationships between the data were visualised, enabling the users to easily infer the knowledge and correlations between data. The results from the user evaluation show that the proposed visualisation system is suitable for both expert and novice users, with or without computer skills. This technique demonstrates the practicability of using a computer assisted-tool by providing cognitive analysis for understanding relationships between data. Therefore, the results benefit not only botanists, but also novice users, especially those that are interested to know more about plants.

    Matched MeSH terms: Trees
  14. Cloning, Production and Characterization of a Glycoside Hydrolase Family 7 Enzyme from the Gut Microbiota of the Termite Coptotermes curvignathus
    Woon JS, King PJH, Mackeen MM, Mahadi NM, Wan Seman WMK, Broughton WJ, et al.
    Mol Biotechnol, 2017 Jul;59(7):271-283.
    PMID: 28573450 DOI: 10.1007/s12033-017-0015-x
    Coptotermes curvignathus is a termite that, owing to its ability to digest living trees, serves as a gold mine for robust industrial enzymes. This unique characteristic reflects the presence of very efficient hydrolytic enzyme systems including cellulases. Transcriptomic analyses of the gut of C. curvignathus revealed that carbohydrate-active enzymes (CAZy) were encoded by 3254 transcripts and that included 69 transcripts encoding glycoside hydrolase family 7 (GHF7) enzymes. Since GHF7 enzymes are useful to the biomass conversion industry, a gene encoding for a GHF7 enzyme (Gh1254) was synthesized, sub-cloned and expressed in the methylotrophic yeast Pichia pastoris. Expressed GH1254 had an apparent molecular mass of 42 kDa, but purification was hampered by its low expression levels in shaken flasks. To obtain more of the enzyme, GH1254 was produced in a bioreactor that resulted in a fourfold increase in crude enzyme levels. The purified enzyme was active towards soluble synthetic substrates such as 4-methylumbelliferyl-β-D-cellobioside, 4-nitrophenyl-β-D-cellobioside and 4-nitrophenyl-β-D-lactoside but was non-hydrolytic towards Avicel or carboxymethyl cellulose. GH1254 catalyzed optimally at 35 °C and maintained 70% of its activity at 25 °C. This enzyme is thus potentially useful in food industries employing low-temperature conditions.
    Matched MeSH terms: Trees
  15. Early Detection of Ganoderma Basal Stem Rot of Oil Palms Using Artificial Neural Network Spectral Analysis
    Ahmadi P, Muharam FM, Ahmad K, Mansor S, Abu Seman I
    Plant Dis, 2017 Jun;101(6):1009-1016.
    PMID: 30682927 DOI: 10.1094/PDIS-12-16-1699-RE
    Ganoderma boninense is a causal agent of basal stem rot (BSR) and is responsible for a significant portion of oil palm (Elaeis guineensis) losses, which can reach US$500 million a year in Southeast Asia. At the early stage of this disease, infected palms are symptomless, which imposes difficulties in detecting the disease. In spite of the availability of tissue and DNA sampling techniques, there is a particular need for replacing costly field data collection methods for detecting Ganoderma in its early stage with a technique derived from spectroscopic and imagery data. Therefore, this study was carried out to apply the artificial neural network (ANN) analysis technique for discriminating and classifying fungal infections in oil palm trees at an early stage using raw, first, and second derivative spectroradiometer datasets. These were acquired from 1,016 spectral signatures of foliar samples in four disease levels (T1: healthy, T2: mildly-infected, T3: moderately infected, and T4: severely infected). Most of the satisfactory results occurred in the visible range, especially in the green wavelength. The healthy oil palms and those which were infected by Ganoderma at an early stage (T2) were classified satisfactorily with an accuracy of 83.3%, and 100.0% in 540 to 550 nm, respectively, by ANN using first derivative spectral data. The results further indicated that the sensitive frond number modeled by ANN provided the highest accuracy of 100.0% for frond number 9 compared with frond 17. This study showed evidence that employment of ANN can predict the early infection of BSR disease on oil palm with a high degree of accuracy.
    Matched MeSH terms: Trees
  16. Fulltext pH dominates variation in tropical soil archaeal diversity and community structure
    Tripathi BM, Kim M, Lai-Hoe A, Shukor NA, Rahim RA, Go R, et al.
    FEMS Microbiol Ecol, 2013 Nov;86(2):303-11.
    PMID: 23773164 DOI: 10.1111/1574-6941.12163
    Little is known of the factors influencing soil archaeal community diversity and composition in the tropics. We sampled soils across a range of forest and nonforest environments in the equatorial tropics of Malaysia, covering a wide range of pH values. DNA was PCR-amplified for the V1-V3 region of the 16S rRNA gene, and 454-pyrosequenced. Soil pH was the best predictor of diversity and community composition of Archaea, being a stronger predictor than land use. Archaeal OTU richness was highest in the most acidic soils. Overall archaeal abundance in tropical soils (determined by qPCR) also decreased at higher pH. This contrasts with the opposite trend previously found in temperate soils. Thaumarcheota group 1.1b was more abundant in alkaline soils, whereas group 1.1c was only detected in acidic soils. These results parallel those found in previous studies in cooler climates, emphasizing niche conservatism among broad archaeal groups. Among the most abundant operational taxonomic units (OTUs), there was clear evidence of niche partitioning by pH. No individual OTU occurred across the entire range of pH values. Overall, the results of this study show that pH plays a major role in structuring tropical soil archaeal communities.
    Matched MeSH terms: Trees
  17. Distinctive phyllosphere bacterial communities in tropical trees
    Kim M, Singh D, Lai-Hoe A, Go R, Abdul Rahim R, Ainuddin AN, et al.
    Microb Ecol, 2012 Apr;63(3):674-81.
    PMID: 21990015 DOI: 10.1007/s00248-011-9953-1
    Recent work has suggested that in temperate and subtropical trees, leaf surface bacterial communities are distinctive to each individual tree species and dominated by Alpha- and Gammaproteobacteria. In order to understand how general this pattern is, we studied the phyllosphere bacterial community on leaves of six species of tropical trees at a rainforest arboretum in Malaysia. This represents the first detailed study of 'true' tropical lowland tree phyllosphere communities. Leaf surface DNA was extracted and pyrosequenced targeting the V1-V3 region of 16S rRNA gene. As was previously found in temperate and subtropical trees, each tree species had a distinctive bacterial community on its leaves, clustering separately from other tree species in an ordination analysis. Bacterial communities in the phyllosphere were unique to plant leaves in that very few operational taxonomic units (0.5%) co-occurred in the surrounding soil environment. A novel and distinctive aspect of tropical phyllosphere communities is that Acidobacteria were one of the most abundant phyla across all samples (on average, 17%), a pattern not previously recognized. Sequences belonging to Acidobacteria were classified into subgroups 1-6 among known 24 subdivisions, and subgroup 1 (84%) was the most abundant group, followed by subgroup 3 (15%). The high abundance of Acidobacteria on leaves of tropical trees indicates that there is a strong relationship between host plants and Acidobacteria in tropical rain forest, which needs to be investigated further. The similarity of phyllosphere bacterial communities amongst the tree species sampled shows a significant tendency to follow host plant phylogeny, with more similar communities on more closely related hosts.
    Matched MeSH terms: Trees/microbiology*
  18. Distinctive bacterial communities in the rhizoplane of four tropical tree species
    Oh YM, Kim M, Lee-Cruz L, Lai-Hoe A, Go R, Ainuddin N, et al.
    Microb Ecol, 2012 Nov;64(4):1018-27.
    PMID: 22767122 DOI: 10.1007/s00248-012-0082-2
    It is known that the microbial community of the rhizosphere is not only influenced by factors such as root exudates, phenology, and nutrient uptake but also by the plant species. However, studies of bacterial communities associated with tropical rainforest tree root surfaces, or rhizoplane, are lacking. Here, we analyzed the bacterial community of root surfaces of four species of native trees, Agathis borneensis, Dipterocarpus kerrii, Dyera costulata, and Gnetum gnemon, and nearby bulk soils, in a rainforest arboretum in Malaysia, using 454 pyrosequencing of the 16S rRNA gene. The rhizoplane bacterial communities for each of the four tree species sampled clustered separately from one another on an ordination, suggesting that these assemblages are linked to chemical and biological characteristics of the host or possibly to the mycorrhizal fungi present. Bacterial communities of the rhizoplane had various similarities to surrounding bulk soils. Acidobacteria, Alphaproteobacteria, and Betaproteobacteria were dominant in rhizoplane communities and in bulk soils from the same depth (0-10 cm). In contrast, the relative abundance of certain bacterial lineages on the rhizoplane was different from that in bulk soils: Bacteroidetes and Betaproteobacteria, which are known as copiotrophs, were much more abundant in the rhizoplane in comparison to bulk soil. At the genus level, Burkholderia, Acidobacterium, Dyella, and Edaphobacter were more abundant in the rhizoplane. Burkholderia, which are known as both pathogens and mutualists of plants, were especially abundant on the rhizoplane of all tree species sampled. The Burkholderia species present included known mutualists of tropical crops and also known N fixers. The host-specific character of tropical tree rhizoplane bacterial communities may have implications for understanding nutrient cycling, recruitment, and structuring of tree species diversity in tropical forests. Such understanding may prove to be useful in both tropical forestry and conservation.
    Matched MeSH terms: Trees/microbiology
  19. Fulltext Impact of logging and forest conversion to oil palm plantations on soil bacterial communities in Borneo
    Lee-Cruz L, Edwards DP, Tripathi BM, Adams JM
    Appl Environ Microbiol, 2013 Dec;79(23):7290-7.
    PMID: 24056463 DOI: 10.1128/AEM.02541-13
    Tropical forests are being rapidly altered by logging and cleared for agriculture. Understanding the effects of these land use changes on soil bacteria, which constitute a large proportion of total biodiversity and perform important ecosystem functions, is a major conservation frontier. Here we studied the effects of logging history and forest conversion to oil palm plantations in Sabah, Borneo, on the soil bacterial community. We used paired-end Illumina sequencing of the 16S rRNA gene, V3 region, to compare the bacterial communities in primary, once-logged, and twice-logged forest and land converted to oil palm plantations. Bacteria were grouped into operational taxonomic units (OTUs) at the 97% similarity level, and OTU richness and local-scale α-diversity showed no difference between the various forest types and oil palm plantations. Focusing on the turnover of bacteria across space, true β-diversity was higher in oil palm plantation soil than in forest soil, whereas community dissimilarity-based metrics of β-diversity were only marginally different between habitats, suggesting that at large scales, oil palm plantation soil could have higher overall γ-diversity than forest soil, driven by a slightly more heterogeneous community across space. Clearance of primary and logged forest for oil palm plantations did, however, significantly impact the composition of soil bacterial communities, reflecting in part the loss of some forest bacteria, whereas primary and logged forests did not differ in composition. Overall, our results suggest that the soil bacteria of tropical forest are to some extent resilient or resistant to logging but that the impacts of forest conversion to oil palm plantations are more severe.
    Matched MeSH terms: Trees*
  20. Fulltext ECG-based prediction algorithm for imminent malignant ventricular arrhythmias using decision tree
    Mandala S, Cai Di T, Sunar MS, Adiwijaya
    PLoS One, 2020;15(5):e0231635.
    PMID: 32407335 DOI: 10.1371/journal.pone.0231635
    Spontaneous prediction of malignant ventricular arrhythmia (MVA) is useful to avoid delay in rescue operations. Recently, researchers have developed several algorithms to predict MVA using various features derived from electrocardiogram (ECG). However, there are several unresolved issues regarding MVA prediction such as the effect of number of ECG features on a prediction remaining unclear, possibility that an alert for occurring MVA may arrive very late and uncertainty in the performance of the algorithm predicting MVA minutes before onset. To overcome the aforementioned problems, this research conducts an in-depth study on the number and types of ECG features that are implemented in a decision tree classifier. In addition, this research also investigates an algorithm's execution time before the occurrence of MVA to minimize delays in warnings for MVA. Lastly, this research aims to study both the sensitivity and specificity of an algorithm to reveal the performance of MVA prediction algorithms from time to time. To strengthen the results of analysis, several classifiers such as support vector machine and naive Bayes are also examined for the purpose of comparison study. There are three phases required to achieve the objectives. The first phase is literature review on existing relevant studies. The second phase deals with design and development of four modules for predicting MVA. Rigorous experiments are performed in the feature selection and classification modules. The results show that eight ECG features with decision tree classifier achieved good prediction performance in terms of execution time and sensitivity. In addition, the results show that the highest percentage for sensitivity and specificity is 95% and 90% respectively, in the fourth 5-minute interval (15.1 minutes-20 minutes) that preceded the onset of an arrhythmia event. Such results imply that the fourth 5-minute interval would be the best time to perform prediction.
    Matched MeSH terms: Decision Trees
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