Origin of a novel protein-coding gene family with similar signal sequence in Schistosoma japonicum

BackgroundEvolution of novel protein-coding genes is the bedrock of adaptive evolution. Recently, we identified six protein-coding genes with similar signal sequence from Schistosoma japonicum egg stage mRNA using signal sequence trap (SST). To find the mechanism underlying the origination of these genes with similar core promoter regions and signal sequence, we adopted an integrated approach utilizing whole genome, transcriptome and proteome database BLAST queries, other bioinformatics tools, and molecular analyses.ResultsOur data, in combination with database analyses showed evidences of expression of these genes both at the mRNA and protein levels exclusively in all developmental stages of S. japonicum. The signal sequence motif was identified in 27 distinct S. japonicum UniGene entries with multiple mRNA transcripts, and in 34 genome contigs distributed within 18 scaffolds with evidence of genome-wide dispersion. No homolog of these genes or similar domain was found in deposited data from any other organism. We observed preponderance of flanking repetitive elements (REs), albeit partial copies, especially of the RTE-like and Perere class at either side of the duplication source locus. The role of REs as major mediators of DNA-level recombination leading to dispersive duplication is discussed with evidence from our analyses. We also identified a stepwise pathway towards functional selection in evolving genes by alternative splicing. Equally, the possible transcription models of some protein-coding representatives of the duplicons are presented with evidence of expression in vitro.ConclusionOur findings contribute to the accumulating evidence of the role of REs in the generation of evolutionary novelties in organisms\u27 genomes

The evaluation of control measures against Schistosoma mekongi in Cambodia by a mathematical model

We constructed a mathematical model for the transmission of Schistosoma mekongi in Cambodia. The simulation of the model will be instrumental in planning schistosomiasis control measures. The model includes two definitive hosts, humans and dogs, as animal reservoirs. Dogs are recognized to play an important role in schistosomiasis transmission in Cambodia. For the purpose of dealing with age-specific prevalence and intensity of infection, the human population was classified into eight age categories in the model. To describe the seasonal fluctuation of the intermediate host population of S. mekongi, the "Post-Spate Survival" hypothesis was adopted for the population dynamics of Neotricula aperta present in the Mekong River. We carried out simulations to evaluate the effect of universal treatment (UT) and targeted mass treatment (TT) with praziquantel on the reduction in prevalence of S. mekongi. The simulations indicated that biyearly UT for 8 years or yearly TT for 5 years after three courses of yearly UT could reduce the prevalence to below 5% when a UT or TT coverage of 85% of inhabitants was achieved. The simulation suggested that the suppression of S. mekongi in Cambodia would be possible by UT or TT with a high coverage rate.</p

Usefulness of Environmental DNA for Surveillance and Control of Schistosomiasis: Detection and Tracking Schistosoma mansoni and Its Intermediate Host Biomphalaria glabrata in Low Endemic Areas of Minas Gerais, Brazil

Poster Session

Analysis of the effectiveness of control measures against Schistosoma mekongi using an intra- and inter-village model in Champasak Province, Lao PDR

Schistosomiasis mekongi is prevalent in the Khong district of Lao PDR, made up of one big island. Khong, and numerous small islands in the Mekong River. Schistosoma mekongi is spread by Neotricula aperta as the intermediate host along the Mekong River. Therefore, even if an epidemic of S. mekongi were stamped out in a certain village, infection may recur if the source of infection is a village located in the upper reaches of the Mekong River. The purpose of this study was to construct a mathematical model for the transmission of S. mekongi among villages from the upper to lower Mekong River to estimate the effect of control measures against it. The chief characteristic of the present model is competence in dealing with the spread of infection among villages through the Mekong River in consideration of the reduction in longevity of cercariae and miracidia and their diffusion in the river. The model also takes into account seasonal fluctuation in the water level of the Mekong River, which affects human behavior in terms of water contact. The results of simulations indicated that the prevalence of schistosomiasis mekongi would be suppressed to a low level for a long time in a village further downstream when universal mass treatment is performed in villages further upstream simultaneously

ナマ シラス ノ セイ ショク ニヨル カンセン ガ ウタガワレタ クジラ フクショクモンジョウチュウ ショウ ノ 1レイ

埼玉県在住の男性・64 歳.2012 年11 月初旬,近医で日本海裂頭条虫症の診断を受け,駆虫目的で本院消化器内科を紹介受診.外来で駆虫治療したところ,全長約250 cm の白色紐状で,全体的に肉厚感のある虫体を排出した.虫体は形態学的特徴より日本海裂頭条虫ではなく,クジラ複殖門条虫が強く疑われたため,遺伝子解析を行った.PCR によって増幅されたcytochrome c oxidase subunit 1 遺伝子(cox1)の全長塩基配列を解析したところ,既知のクジラ複殖門条虫の塩基配列と99%の相同性を示したことから,本症例はクジラ複殖門条虫症と確定した.該当患者は,便に白色紐状物が混入する2&#12316;3 か月前に,生シラスを生食しており,これが感染源となった可能性が高いと考えられた.We have reported a case of infection with whale tapeworm,Diplogonoporus balaenopterae, in Dokkyo MedicalUniversity Hospital. The patient, a 64-year-old Japanesemale, living in Saitama Prefecture was admitted to our hospitalon Nov. 1st 2012, owing to pieces of tapeworm beingdischarged. He was treated with Biltricide&reg; (20 mg/kg)and Magcorol P&reg;( 100 g) in the hospital and he expelled atapeworm about 250 cm, in length along with the scolex afterabout 2 hours of treatment. Based on the morphologicalfeatures of the strobila and the scolex we strongly suspectedthat the tapeworm belongs to the genus Diplogonoporus.To identify the species of the discharged tapeworm, thecomplete cox1 gene was amplified by PCR and the nucleotidesequence was analyzed. The sequence showed 99 %homology against those from D. balaenopterae. From theseresults the patient was diagnosed as a diplogonoporiasiscaused by D. balaenopterae, whale tapeworm. We could notfind any proglottides of tapeworm nor eggs in stools whenwe performed follow up medical examinations three monthsafter treatment. Therefore it can be concluded that the patientwas cured of this disease. In most cases the infectionsource of the whale tapeworm to humans is reported ascoming from marine fish such as sardines and bonitos. Thepatient had frequently consumed various kinds of raw marinefish, and we suspect that the infection source can beattributed to eating raw whitebait

The importance of collecting live fly larvae from a severely decomposed human cadaver in winter. Case report

Abstract: A severely decomposed cadaver was found in a snow-covered mountain forest on January 31, 2010. The cadaver, later identified as a 24-year-old Japanese man, was hanging from under a tree and consisted mainly of skeletal remains. At autopsy, dozens of larvae were observed around the inner cavity of the knee joint, and entomologically they were identified as the third instar larvae of the family Piophilidae (Diptera). It is interesting that the larvae were found alive at the autopsy in January when snow is present. The entomological information supports the information that the man had died around September 8 with the following reason: the location where the victim was found was too cold for the flies to have deposited their eggs; at the man&apos;s death, the ambient temperature was enough high for flies to deposit their eggs; according to the gradual decrease of the ambient temperature, the larvae penetrated into deep lesion with feeding. This is a valuable case demonstrating that live larvae can be obtained from a severely decomposed cadaver found in winter and can support the information about the time of death. This report also validated the importance of collecting Piophilidae flies of severely decomposed cadavers in winter. Key Words: fly larvae, winter, severely decomposed cadaver, forensic entomology, postmortem interval, autopsy. E ntomological information can often be useful in determining both the manner of death (insect activity can sometimes be concentrated around wound sites) and the post mortem interval (PMI) when medical parameters are no longer of value 1) Department of Legal For cadavers with short PMI, detailed information about the species and instars of collected larvae may provide entomological evidence for PMI estimation. Even if the cadavers had been restored for the long time, flies are often observed and provide useful information We report a case in which a victim was found in a snow-covered forest. Although the cadaver consisted mostly of skeletal remains due to postmortem changes, live fly larvae could be collected. As this entomological evidence was well accordance with the information obtained from police investigation, we suggest the importance of collecting live insects even in the severely decomposed cadavers in winter

Evaluation of Crude and Recombinant Antigens of <i>Schistosoma japonicum</i> for the Detection of <i>Schistosoma mekongi</i> Human Infection

Asian schistosomiasis caused by the blood fluke Schistosoma mekongi is endemic in northern Cambodia and Southern Lao People’s Democratic Republic. The disease is mainly diagnosed by stool microscopy. However, serodiagnosis such as enzyme-linked immunosorbent assay (ELISA) with soluble egg antigen (SEA), has been shown to have better sensitivity compared to the stool examination, especially in the settings with a low intensity of infection. To date, no recombinant antigen has been assessed using ELISA for the detection of S. mekongi infection, due to the lack of genome information for this schistosome species. Thus, the objective of this study is to evaluate several recombinant S. japonicum antigens that have been developed in our laboratory for the detection of S. mekongi infection. The crude antigen SjSEA and recombinant antigens Sj7TR, SjPCS, SjPRx-4, and SjChi-3 were evaluated in ELISA using serum samples positive for S. mekongi infection. The cross-reaction was checked using sera positive for Ophistorchis viverrini. ELISA results showed that S. japonicum SEA at low concentrations showed better diagnostic performance than the recombinant antigens tested using the archived serum samples from Cambodia. However, further optimization of the recombinant antigens should be conducted in future studies to improve their diagnostic performance for S. mekongi detection

Elimination of Schistosomiasis Mekongi from Endemic Areas in Cambodia and the Lao People’s Democratic Republic: Current Status and Plans

The areas endemic for schistosomiasis in the Lao People&#8217;s Democratic Republic and in Cambodia were first reported 50 and 60 years ago, respectively. However, the causative parasite Schistosoma mekongi was not recognized as a separate species until 1978. The infection is distributed along a limited part of the Mekong River, regulated by the focal distribution of the intermediate snail host Neotricula aperta. Although more sensitive diagnostics imply a higher figure, the current use of stool examinations suggests that only about 1500 people are presently infected. This well-characterized setting should offer an exemplary potential for the elimination of the disease from its endemic areas; yet, the local topography, reservoir animals, and a dearth of safe water sources make transmission control a challenge. Control activities based on mass drug administration resulted in strong advances, and prevalence was reduced to less than 5% according to stool microscopy. Even so, transmission continues unabated, and the true number of infected people could be as much as 10 times higher than reported. On-going control activities are discussed together with plans for the future

Cloning, Expression and Evaluation of Thioredoxin Peroxidase-1 Antigen for the Serological Diagnosis of Schistosoma mekongi Human Infection

Schistosoma mekongi, a blood fluke that causes Asian zoonotic schistosomiasis, is distributed in communities along the Mekong River in Cambodia and Lao People&rsquo;s Democratic Republic. Decades of employing numerous control measures including mass drug administration using praziquantel have resulted in a decline in the prevalence of schistosomiasis mekongi. This, however, led to a decrease in sensitivity of Kato&ndash;Katz stool microscopy considered as the gold standard in diagnosis. In order to develop a serological assay with high sensitivity and specificity which can replace Kato&ndash;Katz, recombinant S. mekongi thioredoxin peroxidase-1 protein (rSmekTPx-1) was expressed and produced. Diagnostic performance of the rSmekTPx-1 antigen through ELISA for detecting human schistosomiasis was compared with that of recombinant protein of S. japonicum TPx-1 (rSjTPx-1) using serum samples collected from endemic foci in Cambodia. The sensitivity and specificity of rSmekTPx-1 in ELISA were 89.3% and 93.3%, respectively, while those of rSjTPx-1 were 71.4% and 66.7%, respectively. In addition, a higher Kappa value of 0.82 calculated between rSmekTPx-1 antigen ELISA and Kato&ndash;Katz confirmed better agreement than between rSjTPx-1 antigen ELISA and Kato&ndash;Katz (Kappa value 0.38). These results suggest that ELISA with rSmekTPx-1 antigen can be a potential diagnostic method for detecting active human S. mekongi infection