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Estimation of the Size of Dengue and Zika Infection Among Korean Travelers to Southeast Asia and Latin America, 2016-2017

Chu C, Shin ES

Osong Public Health Res Perspect, 2019 Dec;10(6):394-398.
PMID: 31897369 DOI: 10.24171/j.phrp.2019.10.6.10

Objectives: To estimate the number and risk of imported infections resulting from people visiting Asian and Latin American countries.
Methods: The dataset of visitors to 5 Asian countries with dengue were analyzed for 2016 and 2017, and in the Philippines, Thailand and Vietnam, imported cases of zika virus infection were also reported. For zika virus, a single imported case was reported from Brazil in 2016, and 2 imported cases reported from the Maldives in 2017. To understand the transmissibility in 5 Southeast Asian countries, the estimate of the force of infection, i.e., the hazard of infection per year and the average duration of travel has been extracted. Outbound travel numbers were retrieved from the World Tourism Organization, including business travelers.
Results: The incidence of imported dengue in 2016 was estimated at 7.46, 15.00, 2.14, 4.73 and 2.40 per 100,000 travelers visiting Philippines, Indonesia, Thailand, Malaysia and Vietnam, respectively. Similarly, 2.55, 1.65, 1.53, 1.86 and 1.70 per 100,000 travelers in 2017, respectively. It was estimated that there were 60.1 infections (range: from 16.8 to 150.7 infections) with zika virus in Brazil, 2016, and 345.6 infections (range: from 85.4 to 425.5 infections) with zika virus in the Maldives, 2017.
Conclusion: This study emphasizes that dengue and zika virus infections are mild in their nature, and a substantial number of infections may go undetected. An appropriate risk assessment of zika virus infection must use the estimated total size of infections.
Taxonomic notes on eleven species of the subfamily Cteninae (Araneae, Ctenidae) from Asia

Chu C, Lu Y, Li S, Yao Z

Biodivers Data J, 2022;10:e96003.
PMID: 36761640 DOI: 10.3897/BDJ.10.e96003

BACKGROUND: The spider family Ctenidae Keyserling, 1877 has a worldwide distribution with 584 species belonging to 49 genera. Amongst these, 141 species are from Asia, including 130 species assigned to Cteninae Keyserling, 1877.
NEW INFORMATION: Nine new species belonging to three genera of Cteninae are reported from Asia: Amauropelmakrabi sp. n. (female; Krabi, Thailand), Am.phangnga sp. n. (male; Phang Nga, Thailand), Am.saraburi sp. n. (male and female; Saraburi, Thailand); Anahitamedog sp. n. (male and female; Tibet, China); Bowieninhbinh sp. n. (male; Ninh Binh, Vietnam) and B.vinhphuc sp. n. (male and female; Vinh Phuc, Vietnam) from the robustus-species group; B.borneo sp. n. (male; Sabah, Malaysia) from the chinagirl-species group; B.engkilili sp. n. (female; Engkilili, Malaysia); B.sabah sp. n. (male and female; Sabah, Malaysia) from the scarymonsters-species group. The male of An.popa Jäger & Minn, 2015 and the female of B.fascination Jäger, 2022 (robustus-species group) are described for the first time. B.fascination Jäger, 2022 is reported from China for the first time. In addition, the DNA barcodes of all the species in this study were obtained, except for B.vinhphuc sp. n.
A survey of ctenid spiders (Araneae, Ctenidae) from Xishuangbanna Tropical Botanical Garden, Yunnan, China

Chu C, Lu Y, Yao Z, Li S

Biodivers Data J, 2022;10:e87597.
PMID: 36761608 DOI: 10.3897/BDJ.10.e87597

BACKGROUND: Amauropelma Raven, Stumkat & Gray, 2001 currently contains 24 species. It is distributed in Australia, India, Indonesia, Laos and Malaysia. This genus has not been found in China. Ctenus Walckenaer, 1805 comprises 213 known species. This genus is distributed worldwide. Currently, only two species, Ctenuslishuqiang Jäger, 2012 and Ctenusyaeyamensis Yoshida, 1998 are known to occur in China.
NEW INFORMATION: Three new species of ctenid spiders are described from Xishuangbanna Tropical Botanical Garden in Yunnan Province, China: Amauropelmayunnan sp. nov., Ctenusbanna sp. nov. and Ctenusyulin sp. nov. Amauropelma and Ctenusrobustus Thorell, 1897 are reported from China for the first time.
Automated otolith image classification with multiple views: an evaluation on Sciaenidae

Wong JY, Chu C, Chong VC, Dhillon SK, Loh KH

J Fish Biol, 2016 Aug;89(2):1324-44.
PMID: 27364089 DOI: 10.1111/jfb.13039

Combined multiple 2D views (proximal, anterior and ventral aspects) of the sagittal otolith are proposed here as a method to capture shape information for fish classification. Classification performance of single view compared with combined 2D views show improved classification accuracy of the latter, for nine species of Sciaenidae. The effects of shape description methods (shape indices, Procrustes analysis and elliptical Fourier analysis) on classification performance were evaluated. Procrustes analysis and elliptical Fourier analysis perform better than shape indices when single view is considered, but all perform equally well with combined views. A generic content-based image retrieval (CBIR) system that ranks dissimilarity (Procrustes distance) of otolith images was built to search query images without the need for detailed information of side (left or right), aspect (proximal or distal) and direction (positive or negative) of the otolith. Methods for the development of this automated classification system are discussed.
Fulltext Identification and development of TP53 mutation-associated Long non-coding RNAs signature for optimized prognosis assessment and treatment selection in hepatocellular carcinoma

Chu C, Liu D, Wang D, Hu S, Zhang Y

Int J Immunopathol Pharmacol, 2023;37:3946320231211795.
PMID: 37942552 DOI: 10.1177/03946320231211795

BACKGROUND: The TP53 gene is estimated to be mutated in over 50% of tumors, with the majority of tumors exhibiting abnormal TP53 signaling pathways. However, the exploration of TP53 mutation-related LncRNAs in Hepatocellular carcinoma (HCC) remains incomplete. This study aims to identify such LncRNAs and enhance the prognostic accuracy for Hepatoma patients.
MATERIAL AND METHODS: Differential gene expression was identified using the "limma" package in R. Prognosis-related LncRNAs were identified via univariate Cox regression analysis, while a prognostic model was crafted using multivariate Cox regression analysis. Survival analysis was conducted using Kaplan-Meier curves. The precision of the prognostic model was assessed through ROC analysis. Subsequently, the Tumor Immune Dysfunction and Exclusion (TIDE) algorithm were executed on the TCGA dataset via the TIDE database. Fractions of 24 types of immune cell infiltration were obtained from NCI Cancer Research Data Commons using deconvolution techniques. The protein expression levels encoded by specific genes were obtained through the TPCA database.
RESULTS: In this research, we have identified 85 LncRNAs associated with TP53 mutations and developed a corresponding signature referred to as TP53MLncSig. Kaplan-Meier analysis revealed a lower 3-year survival rate in high-risk patients (46.9%) compared to low-risk patients (74.2%). The accuracy of the prognostic TP53MLncSig was further evaluated by calculating the area under the ROC curve. The analysis yielded a 5-year ROC score of 0.793, confirming its effectiveness. Furthermore, a higher score for TP53MLncSig was found to be associated with an increased response rate to immune checkpoint blocker (ICB) therapy (p = .005). Patients possessing high-risk classification exhibited lower levels of P53 protein expression and higher levels of genomic instability.
CONCLUSION: The present study aimed to identify and validate LncRNAs associated with TP53 mutations. We constructed a prognostic model that can predict chemosensitivity and response to ICB therapy in HCC patients. This novel approach sheds light on the role of LncRNAs in TP53 mutation and provides valuable resources for analyzing patient prognosis and treatment selection.
Fulltext The Scorching Truth: Investigating the Impact of Heatwaves on Selangor's Elderly Hospitalisations

Yong KH, Teo YN, Azadbakht M, Phung H, Chu C

Int J Environ Res Public Health, 2023 May 22;20(10).
PMID: 37239636 DOI: 10.3390/ijerph20105910

Global climate change has contributed to the intensity, frequency, and duration of heatwave events. The association between heatwaves and elderly mortality is highly researched in developed countries. In contrast, heatwave impact on hospital admissions has been insufficiently studied worldwide due to data availability and sensitivity. In our opinion, the relationship between heatwaves and hospital admissions is worthwhile to explore as it could have a profound impact on healthcare systems. Therefore, we aimed to investigate the associations between heatwaves and hospitalisations for the elderly by age group in Selangor, Malaysia, from 2010 to 2020. We further explored the impact of heatwaves on the risks of cause-specific hospital admissions across age groups within the elderly. This study applied generalized additive models (GAMs) with the Poisson family and distributed lag models (DLMs) to estimate the effect of heatwaves on hospitalisations. According to the findings, there was no significant increase in hospitalisations for those aged 60 and older during heatwaves; however, a rise in mean apparent temperature (ATmean) by 1 °C significantly increased the risk of hospital admission by 12.9%. Heatwaves had no immediate effects on hospital admissions among elderly patients, but significant delay effects were identified for ATmean with a lag of 0-3 days. The hospital admission rates of the elderly groups started declining after a 5-day average following the heatwave event. Females were found to be relatively more vulnerable than males during heatwave periods. Consequently, these results can provide a reference to improve public health strategies to target elderly people who are at the greatest risk of hospitalisations due to heatwaves. Development of early heatwave and health warning systems for the elderly would assist with preventing and reducing health risks while also minimising the burden on the whole hospital system in Selangor, Malaysia.
Fulltext Using DNA Barcodes to Aid the Identification of Larval Fishes in Tropical Estuarine Waters (Malacca Straits, Malaysia)

Chu C, Loh KH, Ng CC, Ooi AL, Konishi Y, Huang SP, et al.

Zool Stud, 2019;58:e30.
PMID: 31966331 DOI: 10.6620/ZS.2019.58-30

Larval descriptions of tropical marine and coastal fishes are very few, and this taxonomic problem is further exacerbated by the high diversity of fish species in these waters. Nonetheless, accurate larval identification in ecological and early life history studies of larval fishes is crucial for fishery management and habitat protection. The present study aimed to evaluate the usefulness of DNA barcodes to support larval fish identification since conventional dichotomous keys based on morphological traits are not efficient due to the lack of larval traits and the rapid morphological changes during ontogeny. Our molecular analysis uncovered a total of 48 taxa (21 families) from the larval samples collected from the Klang Strait waters encompassing both spawning and nursery grounds of marine and estuarine fishes. Thirty-two (67%) of the larval taxa were identified at the species level, two taxa (4%) at the genus level, and 14 taxa (29%) at family level. The relatively low rate of species-level identification is not necessarily due to the DNA barcoding method per se, but a general lack of reference sequences for speciose and non- commercial fish families such as Gobiidae, Blenniidae, and Callionymidae. Larval morphology remains important in species diagnoses when molecular matches are ambiguous. A lower ethanol percentage (50%) for larva preservation is also useful to keep the body of larvae intact for morphological identification, and to preserve DNA for subsequent molecular analyses. The 10% Chelex resin used to extract DNA is also cost- effective for long term monitoring of larval fishes. Hence, the DNA barcoding method is an effective and easy way to aid the identification of estuarine larval fishes at the species level.
Fulltext Giemsa-stained wet mount based method for reticulocyte quantification: a viable alternative in resource limited or malaria endemic settings

Lee WC, Russell B, Lau YL, Fong MY, Chu C, Sriprawat K, et al.

PLoS One, 2013;8(4):e60303.
PMID: 23565221 DOI: 10.1371/journal.pone.0060303

The quantity of circulating reticulocytes is an important indicator of erythropoietic activity in response to a wide range of haematological pathologies. While most modern laboratories use flow cytometry to quantify reticulocytes, most field laboratories still rely on 'subvital' staining. The specialist 'subvital' stains, New Methylene Blue (NMB) and Brilliant Crésyl Blue are often difficult to procure, toxic, and show inconsistencies between batches. Here we demonstrate the utility of Giemsa's stain (commonly used microbiology and parasitology) in a 'subvital' manner to provide an accurate method to visualize and count reticulocytes in blood samples from normal and malaria-infected individuals.
Fulltext Plasmodium-infected erythrocytes induce secretion of IGFBP7 to form type II rosettes and escape phagocytosis

Lee WC, Russell B, Sobota RM, Ghaffar K, Howland SW, Wong ZX, et al.

Elife, 2020 02 18;9.
PMID: 32066522 DOI: 10.7554/eLife.51546

In malaria, rosetting is described as a phenomenon where an infected erythrocyte (IRBC) is attached to uninfected erythrocytes (URBC). In some studies, rosetting has been associated with malaria pathogenesis. Here, we have identified a new type of rosetting. Using a step-by-step approach, we identified IGFBP7, a protein secreted by monocytes in response to parasite stimulation, as a rosette-stimulator for Plasmodium falciparum- and P. vivax-IRBC. IGFBP7-mediated rosette-stimulation was rapid yet reversible. Unlike type I rosetting that involves direct interaction of rosetting ligands on IRBC and receptors on URBC, the IGFBP7-mediated, type II rosetting requires two additional serum factors, namely von Willebrand factor and thrombospondin-1. These two factors interact with IGFBP7 to mediate rosette formation by the IRBC. Importantly, the IGFBP7-induced type II rosetting hampers phagocytosis of IRBC by host phagocytes.
Fulltext Interactions between all pairs of neighboring trees in 16 forests worldwide reveal details of unique ecological processes in each forest, and provide windows into their evolutionary histories

Wills C, Wang B, Fang S, Wang Y, Jin Y, Lutz J, et al.

PLoS Comput Biol, 2021 Apr;17(4):e1008853.
PMID: 33914731 DOI: 10.1371/journal.pcbi.1008853

When Darwin visited the Galapagos archipelago, he observed that, in spite of the islands' physical similarity, members of species that had dispersed to them recently were beginning to diverge from each other. He postulated that these divergences must have resulted primarily from interactions with sets of other species that had also diverged across these otherwise similar islands. By extrapolation, if Darwin is correct, such complex interactions must be driving species divergences across all ecosystems. However, many current general ecological theories that predict observed distributions of species in ecosystems do not take the details of between-species interactions into account. Here we quantify, in sixteen forest diversity plots (FDPs) worldwide, highly significant negative density-dependent (NDD) components of both conspecific and heterospecific between-tree interactions that affect the trees' distributions, growth, recruitment, and mortality. These interactions decline smoothly in significance with increasing physical distance between trees. They also tend to decline in significance with increasing phylogenetic distance between the trees, but each FDP exhibits its own unique pattern of exceptions to this overall decline. Unique patterns of between-species interactions in ecosystems, of the general type that Darwin postulated, are likely to have contributed to the exceptions. We test the power of our null-model method by using a deliberately modified data set, and show that the method easily identifies the modifications. We examine how some of the exceptions, at the Wind River (USA) FDP, reveal new details of a known allelopathic effect of one of the Wind River gymnosperm species. Finally, we explore how similar analyses can be used to investigate details of many types of interactions in these complex ecosystems, and can provide clues to the evolution of these interactions.
Fulltext A draft genome sequence of the elusive giant squid, Architeuthis dux

da Fonseca RR, Couto A, Machado AM, Brejova B, Albertin CB, Silva F, et al.

Gigascience, 2020 Jan 01;9(1).
PMID: 31942620 DOI: 10.1093/gigascience/giz152

BACKGROUND: The giant squid (Architeuthis dux; Steenstrup, 1857) is an enigmatic giant mollusc with a circumglobal distribution in the deep ocean, except in the high Arctic and Antarctic waters. The elusiveness of the species makes it difficult to study. Thus, having a genome assembled for this deep-sea-dwelling species will allow several pending evolutionary questions to be unlocked.
FINDINGS: We present a draft genome assembly that includes 200 Gb of Illumina reads, 4 Gb of Moleculo synthetic long reads, and 108 Gb of Chicago libraries, with a final size matching the estimated genome size of 2.7 Gb, and a scaffold N50 of 4.8 Mb. We also present an alternative assembly including 27 Gb raw reads generated using the Pacific Biosciences platform. In addition, we sequenced the proteome of the same individual and RNA from 3 different tissue types from 3 other species of squid (Onychoteuthis banksii, Dosidicus gigas, and Sthenoteuthis oualaniensis) to assist genome annotation. We annotated 33,406 protein-coding genes supported by evidence, and the genome completeness estimated by BUSCO reached 92%. Repetitive regions cover 49.17% of the genome.
CONCLUSIONS: This annotated draft genome of A. dux provides a critical resource to investigate the unique traits of this species, including its gigantism and key adaptations to deep-sea environments.
Direct and indirect effects of climate on richness drive the latitudinal diversity gradient in forest trees

Chu C, Lutz JA, Král K, Vrška T, Yin X, Myers JA, et al.

Ecol Lett, 2019 Feb;22(2):245-255.
PMID: 30548766 DOI: 10.1111/ele.13175

Climate is widely recognised as an important determinant of the latitudinal diversity gradient. However, most existing studies make no distinction between direct and indirect effects of climate, which substantially hinders our understanding of how climate constrains biodiversity globally. Using data from 35 large forest plots, we test hypothesised relationships amongst climate, topography, forest structural attributes (stem abundance, tree size variation and stand basal area) and tree species richness to better understand drivers of latitudinal tree diversity patterns. Climate influences tree richness both directly, with more species in warm, moist, aseasonal climates and indirectly, with more species at higher stem abundance. These results imply direct limitation of species diversity by climatic stress and more rapid (co-)evolution and narrower niche partitioning in warm climates. They also support the idea that increased numbers of individuals associated with high primary productivity are partitioned to support a greater number of species.
Fulltext An open dataset of Plasmodium vivax genome variation in 1,895 worldwide samples

MalariaGEN, Adam I, Alam MS, Alemu S, Amaratunga C, Amato R, et al.

Wellcome Open Res, 2022;7:136.
PMID: 35651694 DOI: 10.12688/wellcomeopenres.17795.1

This report describes the MalariaGEN Pv4 dataset, a new release of curated genome variation data on 1,895 samples of Plasmodium vivax collected at 88 worldwide locations between 2001 and 2017. It includes 1,370 new samples contributed by MalariaGEN and VivaxGEN partner studies in addition to previously published samples from these and other sources. We provide genotype calls at over 4.5 million variable positions including over 3 million single nucleotide polymorphisms (SNPs), as well as short indels and tandem duplications. This enlarged dataset highlights major compartments of parasite population structure, with clear differentiation between Africa, Latin America, Oceania, Western Asia and different parts of Southeast Asia. Each sample has been classified for drug resistance to sulfadoxine, pyrimethamine and mefloquine based on known markers at the dhfr, dhps and mdr1 loci. The prevalence of all of these resistance markers was much higher in Southeast Asia and Oceania than elsewhere. This open resource of analysis-ready genome variation data from the MalariaGEN and VivaxGEN networks is driven by our collective goal to advance research into the complex biology of P. vivax and to accelerate genomic surveillance for malaria control and elimination.
Mycorrhizal feedbacks influence global forest structure and diversity

Delavaux CS, LaManna JA, Myers JA, Phillips RP, Aguilar S, Allen D, et al.

Commun Biol, 2023 Oct 19;6(1):1066.
PMID: 37857800 DOI: 10.1038/s42003-023-05410-z

One mechanism proposed to explain high species diversity in tropical systems is strong negative conspecific density dependence (CDD), which reduces recruitment of juveniles in proximity to conspecific adult plants. Although evidence shows that plant-specific soil pathogens can drive negative CDD, trees also form key mutualisms with mycorrhizal fungi, which may counteract these effects. Across 43 large-scale forest plots worldwide, we tested whether ectomycorrhizal tree species exhibit weaker negative CDD than arbuscular mycorrhizal tree species. We further tested for conmycorrhizal density dependence (CMDD) to test for benefit from shared mutualists. We found that the strength of CDD varies systematically with mycorrhizal type, with ectomycorrhizal tree species exhibiting higher sapling densities with increasing adult densities than arbuscular mycorrhizal tree species. Moreover, we found evidence of positive CMDD for tree species of both mycorrhizal types. Collectively, these findings indicate that mycorrhizal interactions likely play a foundational role in global forest diversity patterns and structure.
Fulltext Arbuscular mycorrhizal trees influence the latitudinal beta-diversity gradient of tree communities in forests worldwide

Zhong Y, Chu C, Myers JA, Gilbert GS, Lutz JA, Stillhard J, et al.

Nat Commun, 2021 May 25;12(1):3137.
PMID: 34035260 DOI: 10.1038/s41467-021-23236-3

Arbuscular mycorrhizal (AM) and ectomycorrhizal (EcM) associations are critical for host-tree performance. However, how mycorrhizal associations correlate with the latitudinal tree beta-diversity remains untested. Using a global dataset of 45 forest plots representing 2,804,270 trees across 3840 species, we test how AM and EcM trees contribute to total beta-diversity and its components (turnover and nestedness) of all trees. We find AM rather than EcM trees predominantly contribute to decreasing total beta-diversity and turnover and increasing nestedness with increasing latitude, probably because wide distributions of EcM trees do not generate strong compositional differences among localities. Environmental variables, especially temperature and precipitation, are strongly correlated with beta-diversity patterns for both AM trees and all trees rather than EcM trees. Results support our hypotheses that latitudinal beta-diversity patterns and environmental effects on these patterns are highly dependent on mycorrhizal types. Our findings highlight the importance of AM-dominated forests for conserving global forest biodiversity.

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