MyMedR

Displaying publications 1 - 20 of 34 in total

Abstract:

Sort:

Fulltext Sandwich dot-immunogold filtration assay (DIGFA) for specific immunodiagnosis of active neuroangiostrongyliasis

Eamsobhana P, Tungtrongchitr A, Yong HS, Prasartvit A, Wanachiwanawin D, Gan XX

Parasitology, 2021 Feb;148(2):234-239.
PMID: 33004092 DOI: 10.1017/S0031182020001894

Serological tests may yield false-negative results for specific antibodies detection before or at the early seroconversion phase. Tests that detect circulating antigens of Angiostrongylus cantonensis would therefore be of value in diagnosis to distinguish current or past infection. Here, a quick, easy to perform, portable and inexpensive diagnostic device for detection of 31-kDa A. cantonensis specific antigens had been developed. This sandwich dot-immunogold filtration assay (AcDIGFAAg), for detecting active angiostrongyliasis was produced using anti-A. cantonensis polyclonal antibody dotted on the nitrocellulose membrane as a capture agent and colloidal gold-labelled anti-31 kDa A. cantonensis antibody as a detection agent. A well-defined pink dot, indicating positivity, was seen readily by naked eye within 10-15 min. The AcDIGFAAg detected A. cantonensis-specific antigens in cerebrospinal fluid samples from 4 out of 10 serologically confirmed angiostrongyliasis cases and 2 out of 5 suspected cases with negative anti-A. cantonensis antibodies. Among the 19 patient sera with A. cantonensis infection, 2 showed positive reaction by AcDIGFAAg. No positive AcDIGFAAg reaction was observed in all the serum samples with other parasitic diseases, and the healthy controls. The present 'AcDIGFAAg' enables rapid qualitative detection of the specific 31-kDa antigens of A. cantonensis in clinical samples with potential for application even under resource-limited settings.
Fulltext Prognostic Factors in Recurrent Congenital Muscular Torticollis

Chotigavanichaya C, Phongprapapan P, Wongcharoenwatana J, Eamsobhana P, Ariyawatkul T, Kaewpornsawan K

Malays Orthop J, 2021 Mar;15(1):43-47.
PMID: 33880147 DOI: 10.5704/MOJ.2103.007

Introduction: Congenital muscular torticollis (CMT), primarily resulting from unilateral shortening and fibrosis of the sternocleidomastoid muscle. One of the common surgical complications is recurrent deformity. However, the associations between unipolar or bipolar release, age of the patient, and the recurrence of the disease are unclear. Therefore, the purpose of this study was to evaluate the factors associated with recurrence after surgery.
Materials and Methods: A retrospective review was performed in 47 patients who were diagnosed with CMT and had been treated surgically with unipolar or bipolar release between January 2007 and December 2015. Demographic data (sex, sides, surgical technique, age at time of surgery, period of follow-up, complications and recurrence) were recorded.
Results: Forty-seven patients with an average age of 8.7 years old at time of surgery. Twenty-six patients had right-sided muscular torticollis, while 21 had left-sided. The average follow-up time was 2 years (range, 2-4 years). The average age of unipolar release was 8.8 years old (range, 218 years old), while the average age of bipolar release was 8.7 years old (range, 2-13 years old). Recurrence occurred in 11 patients (9 in unipolar and 2 in bipolar release). Sex, side of deformity, type of surgery and age at time of surgery showed no statistically significant as a factor for recurrence rate, however recurrence of unipolar more than bipolar surgery was nearly two times revealing clinical significance.
Conclusions: Sex, side of deformity, type of surgery and age at time of surgery were not associated with the recurrence deformity.
Phylogenetics and systematics of Angiostrongylus lungworms and related taxa (Nematoda: Metastrongyloidea) inferred from the nuclear small subunit (SSU) ribosomal DNA sequences

Eamsobhana P, Lim PE, Yong HS

J Helminthol, 2015 May;89(3):317-25.
PMID: 24622302 DOI: 10.1017/S0022149X14000108

The Angiostrongylus lungworms are of public health and veterinary concern in many countries. At the family level, the Angiostrongylus lungworms have been included in the family Angiostrongylidae or the family Metastrongylidae. The present study was undertaken to determine the usefulness and suitability of the nuclear 18S (small subunit, SSU) rDNA sequences for differentiating various taxa of the genus Angiostrongylus, as well as to determine the systematics and phylogenetic relationship of Angiostrongylus species and other metastrongyloid taxa. This study revealed six 18S (SSU) haplotypes in A. cantonensis, indicating considerable genetic diversity. The uncorrected pairwise 'p' distances among A. cantonensis ranged from 0 to 0.86%. The 18S (SSU) rDNA sequences unequivocally distinguished the five Angiostrongylus species, confirmed the close relationship of A. cantonensis and A. malaysiensis and that of A. costaricensis and A. dujardini, and were consistent with the family status of Angiostrongylidae and Metastrongylidae. In all cases, the congeneric metastrongyloid species clustered together. There was no supporting evidence to include the genus Skrjabingylus as a member of Metastrongylidae. The genera Aelurostrongylus and Didelphostrongylus were not recovered with Angiostrongylus, indicating polyphyly of the Angiostrongylidae. Of the currently recognized families of Metastrongyloidea, only Crenosomatidae appeared to be monophyletic. In view of the unsettled questions regarding the phylogenetic relationships of various taxa of the metastrongyloid worms, further analyses using more markers and more taxa are warranted.
Fulltext Multigene Phylogeography of Bactrocera caudata (Insecta: Tephritidae): Distinct Genetic Lineages in Northern and Southern Hemispheres

Yong HS, Lim PE, Tan J, Song SL, Suana IW, Eamsobhana P

PLoS One, 2015;10(6):e0129455.
PMID: 26090853 DOI: 10.1371/journal.pone.0129455

Bactrocera caudata is a pest of pumpkin flower. Specimens of B. caudata from the northern hemisphere (mainland Asia) and southern hemisphere (Indonesia) were analysed using the partial DNA sequences of the nuclear 28S rRNA and internal transcribed spacer region 2 (ITS-2) genes, and the mitochondrial cytochrome c oxidase subunit I (COI), cytochrome c oxidase subunit II (COII) and 16S rRNA genes. The COI, COII, 16S rDNA and concatenated COI+COII+16S and COI+COII+16S+28S+ITS-2 nucleotide sequences revealed that B. caudata from the northern hemisphere (Peninsular Malaysia, East Malaysia, Thailand) was distinctly different from the southern hemisphere (Indonesia: Java, Bali and Lombok), without common haplotype between them. Phylogenetic analysis revealed two distinct clades (northern and southern hemispheres), indicating distinct genetic lineage. The uncorrected 'p' distance for the concatenated COI+COII+16S nucleotide sequences between the taxa from the northern and southern hemispheres ('p' = 4.46-4.94%) was several folds higher than the 'p' distance for the taxa in the northern hemisphere ('p' = 0.00-0.77%) and the southern hemisphere ('p' = 0.00%). This distinct difference was also reflected by concatenated COI+COII+16S+28S+ITS-2 nucleotide sequences with an uncorrected 'p' distance of 2.34-2.69% between the taxa of northern and southern hemispheres. In accordance with the type locality the Indonesian taxa belong to the nominal species. Thus the taxa from the northern hemisphere, if they were to constitute a cryptic species of the B. caudata species complex based on molecular data, need to be formally described as a new species. The Thailand and Malaysian B. caudata populations in the northern hemisphere showed distinct genetic structure and phylogeographic pattern.
Molecular phylogeography of Angiostrongylus cantonensis (Nematoda: Angiostrongylidae) and genetic relationships with congeners using cytochrome b gene marker

Yong HS, Eamsobhana P, Song SL, Prasartvit A, Lim PE

Acta Trop, 2015 Aug;148:66-71.
PMID: 25930187 DOI: 10.1016/j.actatropica.2015.04.020

Angiostrongylus cantonensis is an important emerging zoonotic parasite causing human eosinophilic meningitis (or meningoencephalitis) in many parts of the world. To-date there is only a single study using mitochondrial cytochrome b (CYTB) gene to determine its genetic structure in eight geographical localities in Thailand. The present study examined the molecular phylogeography of this rat lungworm and its phylogenetic relationship with congeners using CYTB gene marker. A total of 15 CYTB haplotypes was found in 37 sequences from 14 geographical localities (covering north, west, east, central and south regions) in Thailand. These CYTB haplotypes were distinct from those of A. cantonensis for China and Hawaii. In Thailand, some CYTB haplotypes appeared to be confined to specific geographical localities. The partial CYTB DNA nucleotide sequences separated unequivocally the A. cantonensis isolates of Thailand, China and Hawaii as well as the congeners Angiostrongylus malaysiensis, A. costaricensis and Angiostrongylus vasorum, with A. malaysiensis grouped with A. cantonensis and A. costaricensis grouped with A. vasorum. Likewise the congeners of Metastrongylus and Onchocerca genera could also be clearly differentiated. The present study added two new definitive hosts (Bandicota savilei and Rattus losea) and three new localities (Mae Hong Son in the north, Tak in the west, and Phang Nga in the south) for A. malaysiensis in Thailand, indicating its wide occurrence in the country. Three CYTB haplotypes were found in the Thailand samples of A. malaysiensis. In addition to differentiation of congeners, CYTB gene marker could be used for determining the genetic diversity of a given population/taxon.
Molecular phylogeography and genetic diversity of Angiostrongylus cantonensis and A. malaysiensis (Nematoda: Angiostrongylidae) based on 66-kDa protein gene

Eamsobhana P, Yong HS, Song SL, Gan XX, Prasartvit A, Tungtrongchitr A

Parasitol Int, 2019 Feb;68(1):24-30.
PMID: 30267903 DOI: 10.1016/j.parint.2018.09.006

Angiostrongylus cantonensis is the main causative agent of human angiostrongyliasis. A sibling species, A. malaysiensis has not been unequivocally incriminated to be involved in human infections. To date, there is only a single report on the application of the partial 66-kDa protein gene sequence for molecular differentiation and phylogeny of Angiostrongylus species. Nucleotide sequences of the 66-kDa protein gene of A. cantonensis and A. malaysiensis from Thailand, as well as those of the laboratory strains of A. cantonensis from Thailand and Hawaii, A. cantonensis from Japan and China, A. malaysiensis from Malaysia, and A. costaricensis from Costa Rica, were used for the reconstruction of phylogenetic tree by the maximum likelihood (ML) method and the haplotypes by the median joining (MJ) network. The ML phylogenetic tree contained two major clades with a full support bootstrap value - (1) A. cantonensis and A. malaysiensis, and (2) A. costaricensis. A. costaricensis was basal to A. cantonensis and A. malaysiensis. The genetic distance between A. cantonensis and A. malaysiensis ranged from p = .82% to p = 3.27%, that between A. cantonensis and A. costaricensis from p = 4.90% to p = 5.31%, and that between A. malaysiensis and A. costaricensis was p = 4.49% to p = 5.71%. Both A. cantonensis and A. malaysiensis possess high 66-kDa haplotype diversity. There was no clear separation of the conspecific taxa of A. cantonensis and A. malaysiensis from different geographical regions. A more intensive and extensive sampling with larger sample size may reveal greater haplotype diversity and a better resolved phylogeographical structure of A. cantonensis and A. malaysiensis.
Fulltext Molecular phylogeny of Orthetrum dragonflies reveals cryptic species of Orthetrum pruinosum

Yong HS, Lim PE, Tan J, Ng YF, Eamsobhana P, Suana IW

Sci Rep, 2014 Jul 03;4:5553.
PMID: 24989852 DOI: 10.1038/srep05553

Dragonflies of the genus Orthetrum are members of the suborder Anisoptera, family Libellulidae. There are species pairs whose members are not easily separated from each other by morphological characters. In the present study, the DNA nucleotide sequences of mitochondrial and nuclear genes were employed to elucidate the phylogeny and systematics of Orthetrum dragonflies. Phylogenetic analyses could not resolve the various subfamilies of the family Libellulidae unequivocally. The nuclear 28S rRNA gene is highly conserved and could not resolve congeneric species of Orthetrum. Individual mitochondrial genes (COI, COII, and 16S rRNA) and combination of these genes as well as the nuclear ITS1&2 genes clearly differentiate morphologically similar species, such as the reddish species pairs O. chrysis and O. testaceum, and the bluish-coloured species O. glaucum and O. luzonicum. This study also reveals distinct genetic lineages between O. pruinosum schneideri (occurring in Malaysia) and O. pruinosum neglectum (occurring north of Peninsular Malaysia from India to Japan), indicating these taxa are cryptic species.
Fulltext Mitochondrial Genome Supports Sibling Species of Angiostrongylus costaricensis (Nematoda: Angiostrongylidae)

Yong HS, Song SL, Eamsobhana P, Goh SY, Lim PE, Chow WL, et al.

PLoS One, 2015;10(7):e0134581.
PMID: 26230642 DOI: 10.1371/journal.pone.0134581

Angiostrongylus costaricensis is a zoonotic parasitic nematode that causes abdominal or intestinal angiostrongyliasis in humans. It is endemic to the Americas. Although the mitochondrial genome of the Brazil taxon has been published, there is no available mitochondrial genome data on the Costa Rica taxon. We report here the complete mitochondrial genome of the Costa Rica taxon and its genetic differentiation from the Brazil taxon. The whole mitochondrial genome was obtained from next-generation sequencing of genomic DNA. It had a total length of 13,652 bp, comprising 36 genes (12 protein-coding genes-PCGs, 2 rRNA and 22 tRNA genes) and a control region (A + T rich non-coding region). It is longer than that of the Brazil taxon (13,585 bp). The larger mitogenome size of the Costa Rica taxon is due to the size of the control region as the Brazil taxon has a shorter length (265 bp) than the Costa Rica taxon (318 bp). The size of 6 PCGs and the start codon for ATP6, CYTB and NAD5 genes are different between the Costa Rica and Brazil taxa. Additionally, the two taxa differ in the stop codon of 6 PCGs. Molecular phylogeny based on 12 PCGs was concordant with two rRNA, 22 tRNA and 36 mitochondrial genes. The two taxa have a genetic distance of p = 16.2% based on 12 PCGs, p = 15.3% based on 36 mitochondrial genes, p = 13.1% based on 2 rRNA genes and p = 10.7% based on 22 tRNA genes, indicating status of sibling species. The Costa Rica and Brazil taxa of A. costaricensis are proposed to be accorded specific status as members of a species complex.
Mammomonogamus roundworm (Nematoda: Syngamidae) recovered from the duodenum of a Thai patient: a first and unusual case originating in Thailand

Eamsobhana P, Mongkolporn T, Punthuprapasa P, Yoolek A

Trans R Soc Trop Med Hyg, 2006 Apr;100(4):387-91.
PMID: 16257022

A pair of Mammomonogamus laryngeus roundworms in copula was recovered from the duodenum of a 72-year-old male Thai patient from Kanchanaburi Province. Eggs were also found in the stool of the patient. This is the first case of Mammomonogamus infection originating in Thailand, as the previous two reports from Thailand attributed the infection as originating in Malaysia. The occurrence of adult worms in the duodenum is unusual and differs from previous findings in the larynx, posterior pharynx, tracheal wall and bronchi. This adds a new dimension to the manifestation of the infection.
Fulltext Immunochromatographic test for rapid serological diagnosis of human angiostrongyliasis

Eamsobhana P, Tungtrongchitr A, Wanachiwanawin D, Yong HS

Int J Infect Dis, 2018 Aug;73:69-71.
PMID: 29908250 DOI: 10.1016/j.ijid.2018.06.005

OBJECTIVES: The serological diagnosis of human infection with Angiostrongylus cantonensis remains problematic because there are no commercially available validated tests. Most laboratories use domestically prepared tests such as the enzyme-linked immunosorbent assay (ELISA) or immunoblotting. Since laboratory facilities are not always available in endemic areas, we developed and assessed a rapid lateral flow immunochromatographic assay (AcQuickDx Test) to detect anti-A. cantonensis antibodies in human serum.
METHODS: The test device was assembled with purified 31-kDa glycoprotein as diagnostic antigen and with gold-labelled anti-human immunoglublin-G as the detector reagent. A total of 97 serum samples were tested - 19 samples from clinically diagnosed patients with detectable A. cantonensis-specific antibody in immunoblotting; 43 samples from patients with other parasitic diseases, i.e. gnathostomiasis (n=13), toxocariasis (n=2), trichinellosis (n=2), hookworm infection (n=4), filariasis (n=5), cysticercosis (n=9), paragonimiasis (n=2), opisthorchiasis (n=3), and malaria (n=3); and 35 samples from normal healthy subjects.
RESULTS: The sensitivity, specificity, positive predictive value and negative predictive value of AcQuickDx Test to detect anti-A. cantonensis specific antibodies in serologically confirmed angiostrongyliasis cases, were 100%, 98.72%, 95% and 100%, respectively. Positive AcQuickDx was observed in 1 of 4 cases with hookworm infections. No positive AcQuickDx was observed in cases with other parasitic diseases, and the individual healthy subjects.
CONCLUSIONS: AcQuickDx Test is rapid, highly sensitive and specific, and easy to perform without additional equipment or ancillary supplies. It yields results that are interpreted visually, and possesses a long shelf-life at room temperature. Thus, it can be applied as an additional test for clinical diagnostic support of angiostrongyliasis either in conventional laboratories or for remote areas where laboratory infrastructure is not available.
Genetic variation of NADH dehydrogenase subunit 1 (nad1) mitochondrial gene sequence in adult Necator americanus hookworms recovered from a female patient in Thailand

Eamsobhana P, Yong HS, Roongruangchai K, Tungtrongchitr A, Wanachiwanawin D

Trop Biomed, 2020 Jun 01;37(2):536-541.
PMID: 33612820

Two female and one male adult hookworms were recovered from a female patient in Thailand. Based on gross and microscopic morphology, the three hookworms are members of Necator americanus. Phylogenetic reconstruction based on partial NADH dehydrogenase subunit 1 (nad1) mitochondrial gene sequences shows that these hookworms belong to the same genetic lineage as N. americanus adult worm from Zhejiang, China. The male and female hookworms were genetically distinct, belonging to two different nad1-haplotypes. This is the first report targeting the nad1 gene on the identification and genetic characterization of the human hookworms originated from infected patient. The nad1 gene marker is useful for species and higher taxa differentiation of hookworms.
Genetic diversity of infective larvae of Gnathostoma spinigerum (Nematoda: Gnathostomatidae) in freshwater swamp eels from Thailand

Eamsobhana P, Wanachiwanawin D, Roongruangchai K, Song SL, Yong HS

J Helminthol, 2017 Nov;91(6):767-771.
PMID: 27890039 DOI: 10.1017/S0022149X16000857

Human gnathostomiasis is a food-borne zoonosis caused by a tissue nematode of the genus Gnathostoma. The disease is highly endemic in Asia, including Thailand. The freshwater swamp eel (Monopterus albus), the second intermediate host of the gnathostome nematode, has an important role in transmitting the infection in Thailand. Surveys on the infective larvae of Gnathostoma spinigerum based on morphological features in freshwater swamp eels have been performed continuously and reported in Thailand. However, there is still limited molecular data on intra-species variations of the parasite. In this study, a total of 19 third-stage larvae of morphologically identified G. spinigerum were collected from 437 liver samples of freshwater swamp eels purchased from a large wholesale market in Bangkok, Thailand. Molecular characterization based on mitochondrial cytochrome c oxidase subunit I (COI) sequences was performed to elucidate their genetic variations and phylogenetic relationship. Among the 19 infective larvae recovered from these eels, 16 were sequenced successfully. Phylogenetic analyses inferred from the partial COI gene showed the presence of three distinct COI haplotypes. Our findings confirm the presence of G. spinigerum as the main species in Thailand.
Fulltext Evaluation of dot immunogold filtration assay (DIGFA) for rapid serodiagnosis of eosinophilic meningitis due to Angio-strongylus cantonensis (Nematoda: Metastrongyloidea)

Eamsobhana P, Prasartvit A, Gan XX, Yong HS

Trop Biomed, 2015 Mar;32(1):121-5.
PMID: 25801261

Angiostrongylus cantonensis is the most frequent cause of eosinophilic meningitis in humans in Thailand and worldwide. Because of difficulty of recovering the Angiostrongylus larvae from infected patients, detection of parasite-specific antibodies is used to support clinical diagnosis. This study tested serum samples from eosinophilic meningitis patients and individuals at risk of infection with A. cantonensis to evaluate a recently developed simple and rapid dot-immunogold filtration assay (DIGFA) for detection of specific antibodies against A. cantonensis. Purified 31-kDa glycoprotein of A. cantonensis and protein A colloidal gold conjugate were employed to detect the 31-kDa anti-A. cantonensis antibody in patients sera from the parasite endemic areas of northeast Thailand. The results were compared with those obtained by dot-blot enzyme-linked immunosorbent assay (ELISA) with 31-kDa A. cantonensis antigen. The overall positivity rate of DIGFA and dot-blot ELISA for A. cantonensis infection in 98 clinically diagnosed cases from three highly endemic districts in Khon Kaen province were 39.79% and 37.75%, respectively. Among 86 sera of subjects at risk of infection with A. cantonensis, 24.41% were positive by DIGFA and 23.25% by dot-blot ELISA. There were good correlation between the visual grading of DIGFA and dot-blot ELISA in both groups of defined sera. DIGFA is as sensitive and specific as dot-blot ELISA for confirming eosinophilic meningitis due to A. cantonensis infection, with advantages of simplicity, rapidity and without the use of specific and expensive equipment, and can be used in field settings.
Draft genome of neurotropic nematode parasite Angiostrongylus cantonensis, causative agent of human eosinophilic meningitis

Yong HS, Eamsobhana P, Lim PE, Razali R, Aziz FA, Rosli NS, et al.

Acta Trop, 2015 Aug;148:51-7.
PMID: 25910624 DOI: 10.1016/j.actatropica.2015.04.012

Angiostrongylus cantonensis is a bursate nematode parasite that causes eosinophilic meningitis (or meningoencephalitis) in humans in many parts of the world. The genomic data from A. cantonensis will form a useful resource for comparative genomic and chemogenomic studies to aid the development of diagnostics and therapeutics. We have sequenced, assembled and annotated the genome of A. cantonensis. The genome size is estimated to be ∼260 Mb, with 17,280 genomic scaffolds, 91X coverage, 81.45% for complete and 93.95% for partial score based on CEGMA analysis of genome completeness. The number of predicted genes of ≥300 bp was 17,482. A total of 7737 predicted protein-coding genes of ≥50 amino acids were identified in the assembled genome. Among the proteins of known function, kinases are the most abundant followed by transferases. The draft genome contains 34 excretory-secretory proteins (ES), a minimum of 44 Nematode Astacin (NAS) metalloproteases, 12 Homeobox (HOX) genes, and 30 neurotransmitters. The assembled genome size (260 Mb) is larger than those of Pristionchus pacificus, Caenorhabditis elegans, Necator americanus, Caenorhabditis briggsae, Trichinella spiralis, Brugia malayi and Loa loa, but smaller than Haemonchus contortus and Ascaris suum. The repeat content (25%) is similar to H. contortus. The GC content (41.17%) is lower compared to P. pacificus (42.7%) and H. contortus (43.1%) but higher compared to C. briggsae (37.69%), A. suum (37.9%) and N. americanus (40.2%) while the scaffold N50 is 42,191. This draft genome will facilitate the understanding of many unresolved issues on the parasite and the disorder it causes.
Dot immunogold filtration assay (DIGFA) for the rapid detection of specific antibodies against the rat lungworm Angiostrongylus cantonensis (Nematoda: Metastrongyloidea) using purified 31-kDa antigen

Eamsobhana P, Gan XX, Ma A, Wang Y, Wanachiwanawin D, Yong HS

J Helminthol, 2014 Dec;88(4):396-401.
PMID: 23710755 DOI: 10.1017/S0022149X13000321

A rapid dot immunogold filtration assay (DIGFA) was adopted for specific immunodiagnosis of human cerebral angiostrongyliasis, using purified 31-kDa glycoprotein specific to Angiostrongylus cantonensis as diagnostic antigen and protein A colloidal gold conjugate as antigen-antibody detector. A total of 59 serum samples were assayed - 11 samples from clinically diagnosed patients with detectable A. cantonensis-specific antibody in immunoblotting; 23 samples from patients with other related parasitic diseases, i.e. gnathostomiasis (n= 8), cysticercosis (n= 5), toxocariasis (n= 2), filariasis (n= 4), paragonimiasis (n= 2) and malaria (n= 2); and 25 samples from normal healthy subjects. The sensitivity and specificity of DIGFA to detect anti-A. cantonensis specific antibodies in serologically confirmed angiostrongyliasis cases, were both 100%. No positive DIGFA was observed in cases with other parasitic diseases, and the healthy control subjects. The 3-min DIGFA is as sensitive and specific as the 3-h immunoblot test in angiostrongyliasis confirmed cases that revealed a 31-kDa reactive band. The gold-based DIGFA is more rapid and easier to perform than the traditional enzyme-linked immunosorbent assay (ELISA). The test utilizing purified A. cantonensis antigen is reliable and reproducible for specific immunodiagnosis of human infection with A. cantonensis - thus can be applied as an additional routine test for clinical diagnostic support. Large-scale sero-epidemiological studies in endemic communities in north-east Thailand are under way to evaluate its usefulness under field conditions.
Fulltext Distinct genetic lineages of Bactrocera caudata (Insecta: Tephritidae) revealed by COI and 16S DNA sequences

Lim PE, Tan J, Suana IW, Eamsobhana P, Yong HS

PLoS One, 2012;7(5):e37276.
PMID: 22615962 DOI: 10.1371/journal.pone.0037276

The fruit fly Bactrocera caudata is a pest species of economic importance in Asia. Its larvae feed on the flowers of Cucurbitaceae such as Cucurbita moschata. To-date it is distinguished from related species based on morphological characters. Specimens of B. caudata from Peninsular Malaysia and Indonesia (Bali and Lombok) were analysed using the partial DNA sequences of cytochrome c oxidase subunit I (COI) and 16S rRNA genes. Both gene sequences revealed that B. caudata from Peninsular Malaysia was distinctly different from B. caudata of Bali and Lombok, without common haplotype between them. Phylogenetic analysis revealed two distinct clades, indicating distinct genetic lineage. The uncorrected 'p' distance for COI sequences between B. caudata of Malaysia-Thailand-China and B. caudata of Bali-Lombok was 5.65%, for 16S sequences from 2.76 to 2.99%, and for combined COI and 16S sequences 4.45 to 4.46%. The 'p' values are distinctly different from intraspecific 'p' distance (0-0.23%). Both the B. caudata lineages are distinctly separated from related species in the subgenus Zeugodacus - B. ascita, B. scutellata, B. ishigakiensis, B. diaphora, B. tau, B. cucurbitae, and B. depressa. Molecular phylogenetic analysis indicates that the B. caudata lineages are closely related to B. ascita sp. B, and form a clade with B. scutellata, B. ishigakiensis, B. diaphora and B. ascita sp. A. This study provides additional baseline for the phylogenetic relationships of Bactrocera fruit flies of the subgenus Zeugodacus. Both the COI and 16S genes could be useful markers for the molecular differentiation and phylogenetic analysis of tephritid fruit flies.
Fulltext Distinct genetic clades of Malaysian Copera damselflies and the phylogeny of platycnemine subfamilies

Lim PE, Tan J, Eamsobhana P, Yong HS

Sci Rep, 2013 Oct 17;3:2977.
PMID: 24131999 DOI: 10.1038/srep02977

The phylogenetic relationships of some taxa in the Platycnemidinae at the species and generic levels have been investigated. Phylogenetic trees were generated from both individual mitochondrial encoded COI, COII, 16S rDNA and nuclear encoded 28S rDNA and also combined sequences; these data indicate that the component taxa of the genus Copera belong to two distinct genetic clades - the marginipes group and the annulata group. There was no distinct genetic difference between the red-legged and yellow-legged morphs of C. vittata. Molecular data showed that the annulata group is considered a member of the genus Platycnemis, as originally proposed. The genus Coeliccia, a member of the subfamily Calicnemiinae (Platycnemididae), is not grouped with the Platycnemidinae. The Disparoneurinae of the 'Protoneuridae' showed a closer relationship to the Platycnemidinae than the Calicnemiinae. The dataset supports the placement of the Disparoneurinae as a subfamily of the Platycnemididae. This resolves the monophyly of Platycnemididae.
Differentiating sibling species of Zeugodacus caudatus (Insecta: Tephritidae) by complete mitochondrial genome

Yong HS, Song SL, Lim PE, Eamsobhana P, Suana IW

Genetica, 2016 Oct;144(5):513-521.
PMID: 27502829

Zeugodacus caudatus is a pest of pumpkin flowers. It has a Palearctic and Oriental distribution. We report here the complete mitochondrial genome of the Malaysian and Indonesian samples of Z. caudatus determined by next-generation sequencing of genomic DNA and determine their taxonomic status as sibling species and phylogeny with other taxa of the genus Zeugodacus. The whole mitogenome of both samples possessed 37 genes (13 protein-coding genes-PCGs, 2 rRNA and 22 tRNA genes) and a control region. The mitogenome of the Indonesian sample (15,885 bp) was longer than that of the Malaysian sample (15,866 bp). In both samples, TΨC-loop was absent in trnF and DHU-loop was absent in trnS1. Molecular phylogeny based on 13 PCGs was concordant with 15 mitochondrial genes (13 PCGs and 2 rRNA genes), with the two samples of Z. caudatus forming a sister group and the genus Zeugodacus was monophyletic. The Malaysian and Indonesian samples of Z. caudatus have a genetic distance of p = 7.8 % based on 13 PCGs and p = 7.0 % based on 15 mitochondrial genes, indicating status of sibling species. They are proposed to be accorded specific status as members of a species complex.
Differential abundance and core members of the bacterial community associated with wild male Zeugodacus cucurbitae fruit flies (Insecta: Tephritidae) from three geographical regions of Southeast Asia

Yong HS, Song SL, Eamsobhana P, Pasartvit A, Lim PE

Mol Biol Rep, 2019 Aug;46(4):3765-3776.
PMID: 31012029 DOI: 10.1007/s11033-019-04818-3

Zeugodacus cucurbitae (Coquillet) is one of the most significant and widespread tephritid pest species of agricultural crops. This study reports the bacterial communities associated with Z. cucurbitae from three geographical regions in Southeast Asia (Thailand, Peninsular Malaysia, and Sarawak). The bacterial microbiota were investigated by targeted 16S rRNA gene (V3-V4 region) sequencing using the Illumina Mi-Seq platform. At 97% similarity and filtering at 0.001%, there were seven bacterial phyla and unassigned bacteria, comprising 11 classes, 23 orders, 39 families and 67 genera. The bacterial diversity and richness varied within and among the samples from the three geographical regions. Five phyla were detected for the Sarawak sample, and six each for the Thailand and Peninsular Malaysia samples. Four phyla-Actinobacteria, Bacteroidetes, Firmicutes, and Proteobacteria-were represented in all the fruit fly specimens, forming the core members of the bacterial community. Proteobacteria was the predominant phylum, followed by Bacteroidetes, Firmicutes, and Actinobacteria. Fifty-three genera were represented in the Thailand sample, 56 in the Peninsular Malaysia sample, and 55 in the Sarawak sample. Forty-two genera were present in all the three geographical regions. The predominant core members were order Enterobacteriales (Proeteobacteria), and family Enterobacteriaceae (Enterobacteriales). Klebsiella (Enterobacteriaceae) was the predominant genus and K. oxytoca the predominant species with all specimens having > 10% relative abundance. The results indicate the presence of a great diversity as well as core members of the bacterial community associated with different populations of Z. cucurbitae.
Detection of circulating antigens of Parastrongylus cantonensis in human sera by sandwich ELISA with specific monoclonal antibody

Eamsobhana P, Mak JW, Yong HS

Southeast Asian J. Trop. Med. Public Health, 1995 Dec;26(4):712-5.
PMID: 9139382

A specific monoclonal antibody (AW-3C2) as revealed by ELISA was produced against the adult worm antigens of Parastrongylus cantonensis and used in a sandwich ELISA for the detection of circulating antigens in the sera of parastrongyliasis patients and those with other parasitic diseases. A total of 60 sera was used in this study. Of these, 10 each were from patients with parastrongyliasis, cysticercosis, filariasis, gnathostomiasis, malaria and toxocariasis. The control group consisted of 53 serum samples from normal healthy Thais and Malaysians. The mean +/- optical density (OD) values for the normal Thai and Malaysian groups were 0.126 +/- 0.028 and 0.124 +/- 0.029, respectively. The mean OD values of the parastrongyliasis patient group differed significantly from that of the normal groups as well as those of other parasitic infections. Using a cut-off point of OD +/- 3SD of the control groups as indicating a positive reading, the specificity of the assay with this monoclonal antibody was 100% while the sensitivity was 50%.

Filters

Please provide feedback to Administrator (afdal@afpm.org.my)

External Links