Conservation and diversification of the transcriptomes of adult Paragonimus westermani and P. skrjabini.

BACKGROUND: Paragonimiasis is an important and widespread neglected tropical disease. Fifteen Paragonimus species are human pathogens, but two of these, Paragonimus westermani and P. skrjabini, are responsible for the bulk of human disease. Despite their medical and economic significance, there is limited information on the gene content and expression of Paragonimus lung flukes. RESULTS: The transcriptomes of adult P. westermani and P. skrjabini were studied with deep sequencing technology. Approximately 30 million reads per species were assembled into 21,586 and 25,825 unigenes for P. westermani and P. skrjabini, respectively. Many unigenes showed homology with sequences from other food-borne trematodes, but 1,217 high-confidence Paragonimus-specific unigenes were identified. Analyses indicated that both species have the potential for aerobic and anaerobic metabolism but not de novo fatty acid biosynthesis and that they may interact with host signaling pathways. Some 12,432 P. westermani and P. skrjabini unigenes showed a clear correspondence in bi-directional sequence similarity matches. The expression of shared unigenes was mostly well correlated, but differentially expressed unigenes were identified and shown to be enriched for functions related to proteolysis for P. westermani and microtubule based motility for P. skrjabini. CONCLUSIONS: The assembled transcriptomes of P. westermani and P. skrjabini, inferred proteins, and extensive functional annotations generated for this project (including identified primary sequence similarities to various species, protein domains, biological pathways, predicted proteases, molecular mimics and secreted proteins, etc.) represent a valuable resource for hypothesis driven research on these medically and economically important species.

[Screening and analysis of peptides specifically binding to the schistosomulum tegument of Schistosoma japonicum].

OBJECTIVE: To screen and analyze the peptides in 12 phage-display peptide library specifically binding to the schistosomulum, not cercaria, tegument of Schistosoma japonicum. METHODS: A 12 phage-display peptide library was screened with the S. japonicum schistosomula and cercariae as the target cells for biopanning by degrees, 15 positive clones were picked randomly and deduced by DNA sequencing. According the sequencing result, ELISA test, elution recovery test and immunohistochemical staining were performed to determine the specificity of the phages to the tegument. To further examine its binding properties, the positive peptide conjugated to RhB and recombinant pEGFP-C2 plasmid were similarly synthesized. RESULTS: After 3 rounds of biopanning, the phage recovery rate increased from 3.50 x 10(-5)% to 3.20 x 10(-2)%, indicating that the phage library was successfully enriched in the tegument of schistosomula. The analyzed sequences were identical with 3 peptide sequence of ZL6, ZL4 and ZL1. ELISA showed that the P/N value of MppZL4, MppZL6 and MppZL binding the schistosomulum membrane protein was 6.72, 3.65 and 2.22, while 1.58, 5.15 and 1.20 of binding the membrane protein of cercariae, respectively. Elution recovery test showed that the elution recovery rate of MppZL4 [(4.60 +/- 0.27) x 10(-2)%] was much higher than that of MppZL6 [(2.10 +/- 0.23) x 10(-3)%], MppZL1 [(1.20 +/- 0.28) x 10(-3)%] and M13KE [(1.30 +/- 0.60) x 10(-7)%] (P<0.01). Immunohistochemical staining showed that MppZL4 specifically bound to the tegument of schistosomula with a positive rate of 83.0% (83/100). Fluorescent microscopy revealed that the synthesized RhB-ZL4 bound to the tegument of schistosomula. The ZL4/pEGFP-C2 plasmid was introduced into juvenile S. japonicum and expressed in the parasite. CONCLUSION: The peptide of ZL4 specifically binds to the schistosomulum tegument but not to that of cercaria.

[Pathogen identification of 10 suspected cases of sparganosis mansoni].

OBJECTIVE: To diagnose 10 cases of clinically suspected cases of sparganosis mansoni by pathogen identification. METHODS: In the period from August 2009 to August 2011, 10 biopsy specimens were obtained from 10 patients of four hospitals to identify the pathogen. Among the 10 cases, 4 cases showed abdominal subcutaneous mass, 3 showed eyelid swelling, 1 displayed brain lesions, 1 showed pulmonary mass, and 1 showed pleural effusion. There was one parasite each from three patients with eyelid swelling, and one patient with abdominal subcutaneous mass, which were observed by naked eye and microscope morphologically and histologically. Specimens from other six cases were examined by microscope after paraffin embedding, sectioning, and HE staining. For further identification, the parasite biopsy tissue specimens were detected by immunohistochemistry with Sparganum mansoni-immunized rabbit serum as the primary antibody. RESULTS: Three intact worms, from three patients with eyelid swelling, showed typical S. mansoni morphological characteristics. One residue parasite from the abdominal subcutaneous mass showed network structures and full of calcareous corpuscles in the body under microscope same as that of S. mansoni. The histological structure in three of the six sections showed typically the body wall with folds, which was dense, thick and deeply eosine stained, part of the tegument outside was covered by micro-hairs. In the worm body there was net-like loose structure and calcareous corpuscles without cavity. The structure of the other three worm sections was atypical. The six worm sections were positive by immunohistochemical detection. CONCLUSION: The 10 clinically suspected cases are diagnosed as sparganosis mansoni.

[Preparation of agar-paraffin double-embedded longitudinal sections of Schistosoma japonicum].

Schistosoma japonicum adults are pre-embedded in a double-layer agar and made the block, then dehydrated with alcohol, isobutyl alcohol and n-butyl alcohol. Various staining procedures can be conducted after conventional sectioning and dewaxing. Complete longitudinal serial sections of the pre-embedded worms can be obtained, and the desired sections can be easily located accurately.

[Effect of melatonin on glial fibrillary acidic protein, nuclear factor-kB and synaptophysin expressions in aging mice].

OBJECTIVE: To study the effect of melatonin on the expressions of glial fibrillary acidic protein (GFAP), nuclear factor-κB (NF-κB p65) and synaptophysin in mice of different ages. METHODS: Twenty young male B6C3F1 mice (5.5 months) and 20 aged mice (26 months) were both divided into control and melatonin treatment (daily dose of 0.04 mg/kg) groups. After 2.5 months of treatment, the brain tissues of the mice were collected to examine the expressions of GFAP, NF-κB and SYN by immunohistochemistry. RESULTS: In the control groups, the expression of NF-κB p65 in the brain tissue increased with age, whereas a reverse change was found in melatonin-treated aged rats (P<0.05). Synaptophysin expression also decreased with age, but melatonin treatment significantly enhanced its expression in aged mice (P<0.05). GFAP expression in the brain tissue increased with age regardless of melatonin treatment (P>0.05). CONCLUSION: GFAP expression is almost not affected by melatonin treatment in aged mice. Melatonin can reduce the expression levels of NF-κB p65 and synaptophysin in the brain tissue to protect the brain and slow down the aging process.

[An efficient and accurate method for counting target molecules in phage-display peptide library].

The phage titer of samples representing the low, intermediate and high phage number was respectively determined by the double-layer agar plate (DLAP) method and real-time PCR assay. The two methods accurately measured the titer of samples. The plaques from about 1/3 double-agar layer plates could be used to determine the phage titer. The DLAP experiment should repeat 10 times with 10 microl sample each time, while the within-assay coefficient variation (CV) was 4.93%-30.38%. At the same time, the real-time PCR assay only repeated 3 times with 1 microl phage each time, while CV for within-assay ranged from 0.02% to 0.25%. Results indicated that real-time PCR is a simple and quick method for determining bacteriophage titer.

[Recombinant plasmid ZLW/pEGFP-C2 transfection into schistosomula of Schistosoma japonicum].

OBJECTIVE: To study the efficiency of ZLW/pEGFP-C2 plasmid transfection into Schistosoma japonicum schistosomula and observe its in vitro effect of anti-schistosomula. METHODS: Recombinant plasmid ZLW/pEGFP-C2 was transfected into mechanically transformed schistosomula by immersion in 0.75% DMSO and high concentration of plasmid. Enhanced green fluorescent protein (EGFP) transfected cells were observed under inverted fluorescence microscope. At 48 hours after culture, total RNA and proteins from transfected schistosomula were extracted, and the presence of the transgenes (ZLW and EGFP) in schistosomula were confirmed by RT-PCR and Western blotting. At 24, 48, 72, and 96 hours after transfection, the schistosomula were counted by light microscope with methylene blue staining. pEGFP-C2 empty plasmid group and TBS group served as controls. RESULTS: The transfection rate was about 10%. The fluorescence of ZLW/EGFP protein was mainly localized in the tegument of the worms, especially abundant around oral sucker and ventral sucker. The expected size of 259 bp fragment was successfully amplified by RT-PCR and confirmed by DNA sequencing. Western blotting analysis showed that ZLW/EGFP was expressed in schistosomula. No statistically significant difference was established for schistosomula mortality among ZLW/pEGFP-C2 group (14.0%, 48.8%), pEGFP-C2 group (15.9%, 45.7%) and TBS group (16.9%, 50.3%) at 24 and 48 hours after transfection (P > 0.05). At 72 hours after transfection the mortality rate of ZLW/pEGFP-C2 group (92.7%) was significantly higher than that of pEGFP-C2 group (73.2%) (P < 0.01), and after 96 h the mortality in ZLW/pEGFP-C2 group increased to 100%. CONCLUSION: ZLW/pEGFP-C2 plasmid has been introduced into juvenile S. japonicum by immersion in 0.75% DMSO and high concentration of plasmid, and was expressed in the parasite.

Karyopherin alpha 2 (KPNA2) is associated with the natural resistance to Schistosoma japanicum infection in Microtus fortis.

Microtus fortis is a naturally vertebrate host resistant to Schistosoma japonicum infection. In order to understand the molecular mechanism and identify the molecules related to the natural resistance to S. japanicum infection of M. fortis, we screened a gene pool named gE76 by expression cloning and proved it to have high anti-schistosomula effects in our previous work. In this study we identified a clone named gE76.44. We found that the conditioned medium of pcDNA1.1-gE76.44 caused 14.0% schistosomula death rate in 96 h, which was significantly higher than that of negative control (P<0.05). The gE76.44 was sequenced and the full-length cDNA was 2008 bp with ORF of 1590bp encoding a polypeptide of 529 amino acid residues. Bioinformatics analysis indicated it was the homologue of karyopherin alpha 2 (KPNA2). To further confirm its anti-schistosome activity, we inserted full length of Mf-KPNA2 (KPNA2 of M. fortis) gene into a retroviral expression vector pLXSN and packaged the recombinant virus with PA317 cells. Mice infected with S. japanicum cercariae were administrated by intravenous injection through tail vein and treated with pLXSN-KPNA2. Adult worms and egg reduction were counted after heart perfusion of mice 42 d after infection. We found that compared with the control, mice injected with Mf-KPNA2 had 39.42% worm burden reduction and 76.50% reduction in LEPG (liver eggs per gram) (P<0.01), indicating its anti-schistosome effect of Mf-KPNA2 in vivo. Taken together, the results suggested Mf-KPNA2 as a novel anti-schistosome molecule in vitro and in vivo.

[Screening and characterization of peptides specifically binding to the schistosomulum tegument of Schistosoma japonicum].

OBJECTIVE: To screen and analyze the peptides in 12 phage-display peptide library specifically binding to the schistosomulum tegument of Schistosoma japonicum. METHODS: A 12 phage-display peptide library was screened with the S. japonicum schistosomula as the target cells for biopanning by degrees, positive clones picked randomly were deduced by DNA sequencing. According the sequence seeing result, immunohistochemical staining was performed to determine the specificity of the phages to the tegument. To test their targeting efficacy, the interested phage clones were infused back to the mice infected with S. japonicum, mice were sacrificed 2.5 hours later, and the phage distribution in the liver and the tegument of schistosomula was appraised, respectively. RESULTS: After 3 rounds of biopanning, the phage recovery rate increased from 0.77 x 10(-8) to 0.75 x 10(-5), indicating that the phage library was successfully enriched in the tegument of schistosomula. Seventy-five percent (15/20) of the analyzed sequences were identical with a sequence of QHPRIRKOOOOO. The immunohistochemical stainings showed this sequence specifically binding to the tegument. In vivo titering displayed that this sequence selectively targeted the tegument. CONCLUSION: The peptide of QHPRIRKOOOOO specifically binds to the schistosomulum tegument.

Identification of the resistance of a novel molecule heat shock protein 90alpha (HSP90alpha) in Microtus fortis to Schistosoma japonicum infection.

Microtus fortis is a naturally resistant vertebrate host of Schistosoma japonicum by preventing completion of parasite's life cycle. Sera of M. fortis were found to have anti-schistosome effect in vitro and in vivo. In order to identify genes associated with the anti-schistosome effect of M. fortis, we screened a M. fortis marrow cDNA expression library by expression cloning and identified a 331-bp clone gC14.75. It was the homologue of heat shock protein 90alpha (HSP90alpha). Full-length of M. fortis HSP90alpha gene, Mf-HSP90alpha, was amplified according to gC14.75 and Cricetulus griseus HSP90alpha. To test the potential anti-schistosome function of Mf-HSP90alpha, we prepared conditioned medium of Mf-HSP90alpha and added it to schistosomula cultured in vitro. It caused 27.0% schistosomula death rate in 96h, which was considerably higher than that of negative control. We transferred Mf-HSP90alpha by retroviral expression vector pLXSN into mice to investigate its anti-schistosome effect in vivo. Compared with those of DMEM injection control, mice injected with Mf-HSP90alpha recombinant retrovirus had 40.8% worm burden reduction and 57.9% reduction in liver eggs per gram (LEPG) indicating its anti-schistosome effect in vivo. Taken together, our results suggested Mf-HSP90alpha as a novel anti-schistosome molecule in vitro and in vivo.

[Exploratory thinking on the control technologies of Schistosomiasis japonica].

In this paper, the authors elaborated the difficulties of schistosomiasis control and analyzed shortages and problems of the skills currently used. In order to consolidate the progress in schistosomiasis control and reach the transmission-blocking target, research priorities on the disease control technologies are proposed.

[Analysis of HLA-Cw, KIR2D genetic variations in 2 Chinese populations].

OBJECTIVE: To explore the genetic variations of HLA-Cw and 5 KIR2D loci in 2 Chinese Han populations residing at Southern and Northern mainland China, respectively, and to investigate the HLA-Cw polymorphism of a Mongolian Chinese population. METHODS: HLA-Cw genotyping was performed in a total of 293 healthy individuals including 1 Southern Han population living in Hunan Province (n=112), 1 Northern Han population (n=98) and 1 Mongolian Chinese population(n=83) in the Inner Mongolia Autonomous Region, using polymerase chain reaction-sequence specific primer(PCR-SSP) technique. Dimorphism at residue 80 of domain in the HLA-Cw molecule was examined by an additional set of PCR-SSP reactions. PCR-SSP was also used to detect the presence or absence of inhibitory KIR2DL1/2DL2/2DL3 loci and activating KIR2DS1/2DS2 loci for the 2 Han populations. RESULTS: The main findings were: (1) Very significant frequency difference in the HLA-Cw alleles and dimorphism at codon 80 was detected between Hunan Han and Northern Han population, and between Hunan Han and Mongolian population (P < 0.001),while there was no such difference between the 2 Northern Chinese populations (P> 0.05); (2) There was no significant difference in frequencies of either the 5 individual KIR2D genes or the genotype distributions between the 2 Han populations (P> 0.05); (3) Asn(80)ls/Asn(80), 2DL1+/2DL2-/2DL3+/2DS1-/2DS2- predominated in both Han populations (45/112, 29/98), followed by Asn(80)/Asn(80), 2DL1+/2DL2-/2DL3+/2DS1+/2DS2- (18/112,16/98) and Asn(80)/Lys(80), 2DL1+/2DL2-/2DL3+/2DS1-/2DS2-(11/112,17/98). Among the 12 types of HLA-Cw codon 80 and KIR2D combinations, only Lys(80)/Lys(80), 2DL1+/2DL2-/2DL3+/2DS1-/2DS2- showed marginally significant frequency difference between the 2 Han populations(1/112 vs 8/98; Fisheros P was 0.0134). CONCLUSION: Our study provided the polymorphism data of HLA-Cw gene for 3 Chinese populations with different geographic and/or ethnic background, we further analyzed the distribution of 5 KIR2D receptor genes in 2 Han populations. Our data suggest that in spite of HLA-Cw heterogeneity, remarkable similarities may exist between the Southern and Northern Chinese Han populations at the combinational level of HLA-Cw and KIR2D, which are characterized by preponderant inhibitory signal pathways.

[Biological identification on sub-cultivation cells of Schistosoma japonicum adult worms in vitro].

Cultivation of cells from 30-day old Schistosoma japonicum (S.j) adult worms showed that the growth features of the cells were semi-floating and accumulative. The survival rate of the primary cells, passage cells prior to the 5th generation and recovered cells was all up to 90%. Phases of cell division were observed during cultivation. Chromosome karyotype of the 5th generation cells possessed diploid feature of the blood-flukes (2n=8 in number). Ultrastructure of the 5th generation cells showed that four types of cells in normal morphology and three types of cells in abnormal morphology were both viewed. It is suggested that some of the cells from S.j adult worms were subcultured successfuly in the 1640-40 defined medium.

[Study on the relationship of immune status with severity of schistosomiasis japonica in fishermen in the Dongting Lake].

OBJECTIVE: To investigate the relationship of the immune status and the intensity of infection or the severity of the hepatosplenic pathology among fishermen with schistosomiasis japonica in the Dongting Lake region. METHODS: Inquiring and physical examination (IPE), stool examination, B-ultrasonography of the liver and spleen, flow cytometry, turbidimetry and ELISA were undertaken to acquire or determine the intensity of infection (EPG in stool), pathological change in the liver and spleen and the level of cellular and humoral immunity. Data were analyzed with SPSS 10.0 statistics software. RESULTS: Compared with subjects from non-endemic area, the CD4+ T cells and the CD4+/CD8+ ratio in fishing population in the endemic area significantly decreased. The decrease of the CD4+/CD8+ ratio was more significant among population with positive stool exam and with the increase of EPG and/or severity of pathological change in the liver and spleen. Contrarily, the level of the total IgM and the anti-SEA IgG in serum from fishing population in the endemic area was significantly higher than those from non-endemic area. High level serum antibodies in those stool positives were remarkable with the increase of EPG and/or the severity of hepatosplenic pathological change. The total IgA increased considerably in the subjects with significant pathological change of the liver and spleen. A high total IgG was only detected in those stool positives. CONCLUSION: The immune status in fishermen with schistosomiasis in the Dongting Lake showed a suppressed cellular immunity and a hyper functioning humoral immune response. The imbalance of the immunity was related to the increase of the intensity of infection and the progress of the hepatosplenic pathology.

[Analysis on morbidity and chemotherapy effects of Schistosoma japonicum infection in fishermen on Dongting Lake].

OBJECTIVE: To clarify and evaluate the morbidity of schistosome infection and the effectiveness of chemotherapy among fishermen on East Dongting Lake. METHODS: Information on water-contact, history of infection and of praziquantel (PZQ) treatment among fishermen was collected. Kato-Katz method and miracidium hatching test were applied to detect the pathogens in stool specimen. Serum antibodies against soluble egg antigen (SEA) were detected with ELISA and IHA. B-ultrasonic examination was used to determine the pathological changes of liver and spleen. Chemotherapy [PZQ 40 mg/(kg x d)] was given to the fishermen followed by a re-examination after a transmission season. RESULTS: The first investigation (six months before chemotherapy) showed that among 268 people inquired, 90.7% were frequently or intermittently contacting water, 24.0% were treated with PZQ each year, 39.4% had never been treated in the recent five years. Stool positive rate was 68.1% (111/163) and the geometric mean eggs per gram feces (EPG) were 48.77. Males had a higher infection rate (76.0%) and intensity (62.97 EPG) compared with that of females (58.7% infection rate and 30.42 EPG). The highest positive rate (83.3%) was in the age group of 11 to 20 years old. The prevalence of those who frequently or intermittently contacted water and were never treated before was 76.3% (106/139) and 79.7% (51/64), respectively. Serological positive rate was 88.0% (IHA) or 78.7% (ELISA). B-ultrasound revealed 77.4% (82/106) of the fishermen showing pathological changes in liver and/or spleen due to schistosomiasis. 37.7% of the patients showed II-III stage liver fibrosis (male: 53.0%, female: 15%), 58.5% hepatomegaly and 19.8% splenomegaly. The second investigation (six months after chemotherapy with PZQ) showed a stool positive rate of 35.4% and an average EPG 36.13 in the treatment group which were considerably lower than 56.5% infection rate and 68.47 EPG in the group without treatment. In 39 patients treated, the reversion rate from egg positive to negative was 48.7%, pathological change in liver and spleen declined by 40.6%. CONCLUSION: The prevalence and morbidity of schistosomiasis in fishermen on Dongting Lake were high due to frequent exposure to the affected water, and chemotherapy can effectively reduce the prevalence, the intensity of infection and morbidity of the fishermen.

[Identification of the source and types of cells of Schistosoma japonicum by histochemical staining].

OBJECTIVE: To study the possibility on in vitro identifying the source or kinds of cells from Schistosoma japonicum (S.j). METHODS: The cells from digested tissues of 18 days old schistosomula were smeared on slides. The adult worms of S.j were used for making paraffin sections. The cell smears and tissue sections were stained with 6 different methods of histochemical staining including Periodic Acid-Schiff (PAS), Argyrophil reaction (by Grimeliu's), Picric acid-acid Fuchsin (by Van Gieson, VG), Thionin, Toluidine blue (TB) and Hematoxylin-Eosin (HE) staining parallelly. The results were judged through inspecting the specific color of the cells on smears referring to location of corresponding staining of paraffin sections of adult worm tissues under light microscopy. RESULTS: Vitelline gland cells, mother germ cells, nerve cells, digestive epithelial cells, muscular cells and mast cells were shown clearly. The stainings of VG, PAS and Thionin demonstrated cell types coinciding to histological location. The TB staining did not find red-purple mast cell in tissue sections but one in cell smears. The Grimeliu's argyrophil reaction displayed that intestine wall of tissure sections and stained cells of cell smears were in black clearly. CONCLUSION: HE staining together with histochemical staining can reliably and rapidly distinguish the cell types of Schistosoma japonicum.