Displaying publications 1 - 20 of 91 in total

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  1. Zuha RM, Omar B
    Parasitol Res, 2014 Jun;113(6):2285-94.
    PMID: 24728523 DOI: 10.1007/s00436-014-3883-z
    Cosmopolitan scuttle fly, Megaselia scalaris (Loew) (Diptera: Phoridae) is one of the commonest forensic species recorded colonizing human corpse indoors and in concealed environment. The occurrence of this species in such environments provides a higher evidential value to assist estimation of postmortem interval (PMI) compared to other forensically important dipterans. However, developmental and size data of M. scalaris are still lacking and they are derived from a limited range of thermal values. The objective of this study is to develop the growth model of M. scalaris by emphasizing the size range of larvae and puparia at different constant temperatures. This species was reared in six replicates at eight varying constant temperatures ranging from 23 to 36 °C and cow's liver was provided as food source. Larvae and puparia were sampled at set time intervals and measured by their length and weight. Because interpretation of forensic entomological evidence is subject to application of different techniques, development of M. scalaris is expressed herein by using developmental table, length/morphological stage diagrams and linear/nonlinear estimation methods. From the findings, it is very important to highlight that sexual dimorphism of M. scalaris during post feeding larva and pupa stage could be observed based on size and developmental periods. Mean length and weight ratios of male to female puparia are approximately 0.8 and 0.3-0.5, respectively, indicating sexual dimorphism of this species. Developmental period in female are 4.0-11.4 h (post feeding larval stage), 3.7-24.0 h (pupal stage), and 3.0-20.1 h (total developmental period) longer in male. Due to this dimorphism, PMI estimation using M. scalaris post feeding larva or puparium specimens must be carried out carefully by to avoid inaccuracy and misinterpretation.
  2. Borkhanuddin MH, Cech G, Mazelan S, Shaharom-Harrison F, Molnár K, Székely C
    Parasitol Res, 2014 Jan;113(1):29-37.
    PMID: 24096611 DOI: 10.1007/s00436-013-3622-x
    The authors studied the myxosporean infection of wild gobiid fishes (Perciformes: Gobioidei) in the Merang Estuary of Terengganu, Malaysia, and described Myxobolus ophiocarae sp. n. in Ophiocara porocephala. Several myxosporean plasmodia were found intralamellarly within the gill filaments. The spores differed from those of other Myxobolus species previously recorded on gobiid fishes. They were round in valvular view and lens-shaped in sutural view, and had two equal-sized, pyriform polar capsules with polar filaments having six to seven turns. The spores measured 10.34 × 8.79 × 4.53 μm. The 18S rDNA sequence of M. ophiocarae sp. n., based on a contiguous sequence of 1,789 base pairs, differed from any other Myxobolus spp. in GenBank. Phylogenetic analysis of the 18S rDNA gene revealed that this species showed the closest similarity to Myxobolus nagaraensis, Myxobolus lentisuturalis, and Myxobolus cultus.
  3. Kumarasamy V, Kuppusamy UR, Samudi C, Kumar S
    Parasitol Res, 2013 Oct;112(10):3551-5.
    PMID: 23933809 DOI: 10.1007/s00436-013-3538-5
    Blastocystis sp. is a commonly found intestinal microorganism and was reported to cause many nonspecific gastrointestinal symptoms. Various subtypes have been previously reported, and the pathogenicity of different subtypes of Blastocystis is unclear and remains as a controversial issue. A recent study has shown that the Blastocystis antigen isolated from an unknown subtype could facilitate the proliferation of colon cancer cells. Current study was conducted to compare the effect of solubilized antigen isolated from five different subtypes of Blastocystis on colon cancer cells, HCT116. A statistically significant proliferation of these cells was observed when exposed to 1.0 μg/ml solubilized antigen isolated from subtype 3 Blastocystis (37.22%, p < 0.05). Real-time polymerase chain reaction demonstrated the upregulation of Th2 cytokines especially transforming growth factor beta in subtype 3-treated cancer cells (p < 0.01, 3.71-fold difference). Of interest, subtype 3 Blastocystis antigen also caused a significantly higher upregulation of cathepsin B (subtypes 1 and 2, p < 0.01; subtypes 4 and 5, p < 0.001; 6.71-fold difference) which lead to the postulation that it may enhance the exacerbation of existing colon cancer cells by weakening the cellular immune response. The dysregulation of IFN-γ and p53 expression also suggest Blastocystis as a proponent of carcinogenesis. Therefore, it is very likely for subtype 3 Blastocystis to have higher pathogenic potential as it caused an increased propagation of cancer cells and substantial amount of inflammatory reaction compared to other subtypes.
  4. Cheah SX, Tay JW, Chan LK, Jaal Z
    Parasitol Res, 2013 Sep;112(9):3275-82.
    PMID: 23835922 DOI: 10.1007/s00436-013-3506-0
    This study focuses on the larvicidal, oviposition, and ovicidal effects of a crude extract of Artemisia annua against Aedes aegypti, Anopheles sinensis, and Culex quinquefasciatus. Dried cells of Artemisia annua from cell suspension cultures were extracted using hexane. The extract showed moderate larvicidal effects against mosquitoes. At 24-h post treatment, the LC50 values for Anopheles sinensis, Aedes aegypti, and Culex quinquefasciatus were recorded as 244.55, 276.14, and 374.99 ppm, respectively. The percentage mortality of larvae was directly proportional to the tested concentration. Anopheles sinensis was found to be the most susceptible species, whereas Culex quinquefasciatus was the most tolerant to the Artemisia annua extract. The results indicated that the Artemisia annua extract showed concentration-dependent oviposition deterrent activity and had a strong deterrent effect. At 500 ppm, the percentage effective repellency was more than 85% compared with the control group for all the species, with oviposition activity index values of -0.94, -0.95, and -0.78 for Aedes aegypti, Anopheles sinensis, and Culex quinquefasciatus, respectively. In the ovicidal assay, the percentage hatchability of eggs after treatment with 500 ppm of Artemisia annua extract was significantly lower than the control, with values of 48.84 ± 4.08, 38.42 ± 3.67, and 79.35 ± 2.09% for Aedes aegypti, Anopheles sinensis, and Culex quinquefasciatus, respectively. Artemisia annua was found to be more effective against Aedes aegypti and Anopheles sinensis compared with Culex quinquefasciatus. This study indicated that crude extract of A. annua could be a potential alternative for use in vector management programs.
  5. Onichandran S, Kumar T, Lim YA, Sawangjaroen N, Andiappan H, Salibay CC, et al.
    Parasitol Res, 2013 Dec;112(12):4185-91.
    PMID: 24046263 DOI: 10.1007/s00436-013-3610-1
    The objective of this study was to assess the physico-chemical parameters and waterborne parasites in selected recreational lakes from Malaysia. Samples were collected from seven stations of Recreational Lake A (RL-A) and six stations of Recreational Lake B (RL-B). The samples were processed to detect the presence of Giardia spp. and Cryptosporidium spp. using immunomagnetic separation kit, helminth eggs or ova by bright field microscopy and Acanthamoeba spp. by cultivation in non-nutrient agar. Chemical parameters such as ammonia, chlorine, fluoride, nitrate and nitrite and physical parameters such as dissolved oxygen, electrical conductivity, pH, salinity, temperature and total dissolved solid were also measured. Both lakes were freshwater with salinity ranging from 0.05 to 0.09 ppt. Most stations of these lakes were contaminated with Cryptosporidium spp., Giardia spp., Ascaris spp. and hookworm. Schistosoma spp. was found in RL-B only, while Acanthamoeba spp. was found in all stations. Of all sampling sites, station 5 of RL-B is the most contaminated. Linear regression and correlation analysis revealed that Giardia spp. and Schistosoma spp. showed a significant negative correlation with turbidity (p 
  6. Fuehrer HP, Treiber M, Silbermayr K, Baumann TA, Swoboda P, Joachim A, et al.
    Parasitol Res, 2013 Jun;112(6):2393-5.
    PMID: 23358737 DOI: 10.1007/s00436-013-3311-9
    Dirofilaria immitis is a parasite of domestic and wild canids and felids in tropical, subtropical and temperate regions throughout the world. The canine heartworm (D. immitis) is the causative agent of canine and feline cardiopulmonary dirofilariasis. This parasite is known to cause a zoonotic disease, namely human pulmonary dirofilariasis. D. immitis is known to be endemic in several South and Southeast Asian countries (e.g. India and Malaysia), but there has previously been no information about the presence of this pathogen in Bangladesh. We present a case of canine dirofilariasis caused by D. immitis in rural southeastern Bangladesh. A male filaroid nematode (95 mm in length and 1.94 mm in width) was identified in the heart of a dog. Species classification was performed by microscopy and molecular tools. Sequence analysis revealed a 100 % identity within the mitochondrial cytochrome c oxidase I (CO1) gene to two Chinese and one Australian D. immitis samples. Usually, dogs stay outside overnight with a high risk to get infected with D. immitis via nocturnal mosquito vectors, which may lead to high prevalences of this pathogen in the canine population and thus increase the risk of human infections with this neglected parasitic disease.
  7. Ching XT, Lau YL, Fong MY, Nissapatorn V
    Parasitol Res, 2013 Mar;112(3):1229-36.
    PMID: 23274488 DOI: 10.1007/s00436-012-3255-5
    Toxoplasma gondii infects all warm-blooded animals including humans, causing serious public health problems and great economic loss in the food industry. Commonly used serological tests involve preparation of whole Toxoplasma lysate antigens from tachyzoites which are costly and hazardous. An alternative method for better antigen production involving the prokaryotic expression system was therefore used in this study. Recombinant dense granular protein, GRA2, was successfully cloned, expressed, and purified in Escherichia coli, BL21 (DE3) pLysS. The potential of this purified antigen for diagnosis of human infections was evaluated through western blot analysis against 100 human serum samples. Results showed that the rGRA2 protein has 100 and 61.5 % sensitivity towards acute and chronic infection, respectively, in T. gondii-infected humans, indicating that this protein is useful in differentiating present and past infections. Therefore, it is suitable to be used as a sensitive and specific molecular marker for the serodiagnosis of Toxoplasma infection in both humans and animals.
  8. Ahmad AF, Hadip F, Ngui R, Lim YA, Mahmud R
    Parasitol Res, 2013 Aug;112(8):2811-6.
    PMID: 23666229 DOI: 10.1007/s00436-013-3450-z
    Detection of Strongyloides stercoralis infection particularly in asymptomatic individuals is often hampered due to the lack of standard diagnostic tools. In this study, the use of serological and molecular approaches were investigated for the detection of S. stercoralis infection among an Orang Asli (indigenous) community following a preliminary detection by microscopic examination of faecal samples. Out of 54 individuals studied, 17/54 (31.5%) were detected to be positive for S. stercoralis infection by enzyme-linked immunosorbent assay (ELISA), compared to 0/54 (0%) by faecal examination. Further confirmation performed by a nested polymerase chain reaction (PCR) using DNA extracted from faecal samples of these 17 individuals yielded 3/17 (17.6%) positives for S. stercoralis DNA amplification. No amplification was seen with the other 37 faecal samples, which were negative by microscopy and ELISA. As the high ELISA positive results were suspected to be false-positives, ELISA is not recommended for use as a detection tool but may be beneficial for evaluating the effectiveness of anti-Strongyloides drugs. The present finding indicated that PCR should be considered as an alternative diagnostic tool for the detection of S. stercoralis infection.
  9. Zuha RM, Razak TA, Ahmad NW, Omar B
    Parasitol Res, 2012 Nov;111(5):2179-87.
    PMID: 22886544 DOI: 10.1007/s00436-012-3070-z
    In forensic entomology, breeding of fly larvae in a controlled laboratory environment using animal tissue is a common technique to obtain insect developmental time for the estimation of postmortem interval. Previous studies on growth media are mostly on the effect of different diets on fly development. However, the interaction effects between temperature and food type used have not been explored. The objective of this study was to compare the use of cow's liver agar and raw liver on the development of a forensically important fly, Megaselia scalaris (Loew). This study also determined the interaction between different temperatures and different food types on the growth of this species. A total of 100 M. scalaris eggs were transferred into each of the two media mentioned above. Liver agar was prepared by adding dried ground liver into nutrient agar, whilst raw liver was naturally prepared from the same animal source. This experiment was conducted at 27, 30 and 33 °C in an incubator in a continuously dark condition. Length and weight of larvae, puparia and adult samples were determined. Total developmental times for larvae feeding on liver agar at each temperature were approximately 7-15 h slower than those feeding on raw liver. Survival rates were almost equal in both diets but were lower at 33 °C. Mean larva length in both diets did not differ significantly at all temperatures, but larvae feeding on liver agar had lower mean weight values than those in raw liver at 30 and 33 °C. The effect of temperature was significant in female puparia weight and male adult weight whereas the effect of diet types was significant in both male and female puparia size and weight. Interaction effects of temperature and food type on M. scalaris puparium size and adult weight were significant, indicating that puparium size and adult weight depended on both food type and temperature. This experiment highlighted the use of cow's liver agar as an alternative diet to breed M. scalaris in the laboratory and the importance of considering the interaction effect between temperatures and food types when deciding the most suitable medium in fly larva rearing.
  10. Al-Rofaai A, Rahman WA, Abdulghani M
    Parasitol Res, 2013 Feb;112(2):893-8.
    PMID: 22961237 DOI: 10.1007/s00436-012-3113-5
    The sensitivity of larval paralysis assay (LPA) and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide-formazan (MTT-formazan) assay was compared to evaluate the anthelmintic activity of plant extracts. In this study, the methanolic extract of Azadirachta indica (neem) was evaluated for its activity against the infective-stage larvae (L(3)) of susceptible and resistant Haemonchus contortus strains using the two aforementioned assays. In both in vitro assays, the same serial concentrations of the extract were used, and the median lethal concentrations were determined to compare the sensitivity of both assays. The results revealed a significant difference (P < 0.05) in the sensitivity of the LPA and the MTT-formazan assay. The MTT-formazan assay is more feasible for practical applications because it measured the L(3) mortality more accurately than LPA. This study may help find a suitable assay for investigating the anthelmintic activity of plant extracts against trichostrongylid nematodes.
  11. Tan TC, Tan PC, Sharma R, Sugnaseelan S, Suresh KG
    Parasitol Res, 2013 Jan;112(1):85-9.
    PMID: 22961236 DOI: 10.1007/s00436-012-3107-3
    Blastocystis sp. is a common intestinal parasite found in humans and animals. The possibility of zoonotic transmission to humans from livestock especially goats led us to investigate the genetic diversity of caprine Blastocystis sp. obtained from five different farms in Peninsular Malaysia. Moreover, there is a lack of information on the prevalence as well as genetic diversity of Blastocystis sp. in goat worldwide. Results showed that 73/236 (30.9 %) of the goats were found to be positive for Blastocystis infection. The most predominant Blastocystis sp. subtype was ST1 (60.3 %) followed by ST7 (41.1 %), ST6 (41.1 %), and ST3 (11.0 %) when amplified by PCR using sequenced-tagged site (STS) primers. Four farms had goats infected only with ST1 whereas the fifth showed mixed infections with multiple STs. The proximity of the fifth farm to human dwellings, nearby domesticated animals and grass land as opposed to a sterile captive environment in the first four farms may account for the multiple STs seen in the fifth farm. Since ST1, ST3, ST6 and ST 7 were previously reported in human infection worldwide in particular Malaysia, the potential of the zoonotic transmission of blastocystosis should not be disregarded. The implications of different farm management systems on the distribution of Blastocystis sp. STs are discussed.
  12. Székely C, Shaharom F, Cech G, Mohamed K, Zin NA, Borkhanuddin MH, et al.
    Parasitol Res, 2012 Oct;111(4):1749-56.
    PMID: 22782473
    Tor tambroides, a common and appreciated cyprinid fish of the Tasik Kenyir water reservoir in Malaysia, is one of the species selected for propagation. This fish was first successfully propagated in Malaysia by the Department of Agriculture, Sarawak, Malaysia, and the breeding program continued throughout the country. The gills were frequently infected by a Myxobolus species to be described as Myxobolus tambroides sp. n. The small, 50 to 70 μm, round plasmodia of this species is located intralamellarly. Plasmodia were filled with pyriform myxospores, 9.9 and 7.4 μm wide. In sutural view, the caudal end of the myxospores had a distinctive valvular groove, parallel with the suture. Plasmodia caused deformations on the affected and the neighbouring gill lamellae. The 18S rDNA sequence of M. tambroides sp.n. did not show a close relationship with any other Myxobolus spp., represented in the GenBank. This might be an emerging parasite likely to impact the propagation of this fish.
  13. Chan KH, Chandramathi S, Suresh K, Chua KH, Kuppusamy UR
    Parasitol Res, 2012 Jun;110(6):2475-80.
    PMID: 22278727 DOI: 10.1007/s00436-011-2788-3
    The pathogenesis of Blastocystis hominis in human hosts has always been a matter of debate as it is present in both symptomatic and asymptomatic individuals. A recent report showed that B. hominis isolated from an asymptomatic individual could facilitate the proliferation and growth of existing cancer cells while having the potential to downregulate the host immune response. The present study investigated the differences between the effects of symptomatic and asymptomatic derived solubilized antigen of B. hominis (Blasto-Ag) on the cell viability and proliferation of colorectal cancer cells. Besides that, the gene expression of cytokine and nuclear transcriptional factors in response to the symptomatic and asymptomatic B. hominis antigen in HCT116 was also compared. In the current study, an increase in cell proliferation was observed in HCT116 cells which led to the speculation that B. hominis infection could facilitate the growth of colorectal cancer cells. In addition, a more significant upregulation of Th2 cytokines observed in HCT116 may lead to the postulation that symptomatic Blasto-Ag may have the potential in weakening the cellular immune response, allowing the progression of existing tumor cells. The upregulation of nuclear factor kappa light chain enhancer of activated B cells (NF-κB) was observed in HCT116 exposed to symptomatic Blasto-Ag, while asymptomatic Blasto-Ag exhibited an insignificant effect on NF-κB gene expression in HCT116. HCT116 cells exposed to symptomatic and asymptomatic Blasto-Ag caused a significant upregulation of CTSB which lead to the postulation that the Blasto-Ag may enhance the invasive and metastasis properties of colorectal cancer. In conclusion, antigen isolated from a symptomatic individual is more pathogenic as compared to asymptomatic isolates as it caused a more extensive inflammatory reaction as well as more enhanced proliferation of cancer cells.
  14. Lee IL, Tan TC, Tan PC, Nanthiney DR, Biraj MK, Surendra KM, et al.
    Parasitol Res, 2012 Apr;110(4):1553-62.
    PMID: 22076050 DOI: 10.1007/s00436-011-2665-0
    Blastocystis sp. is a common intestinal parasite. To date, there have been sporadic and scanty studies on Blastocystis sp. carried out in rural communities in Nepal. We surveyed the prevalence of Blastocystis sp. and its possible associated risk factors, and reported the predominant Blastocystis sp. subtype in two rural communities, Bolde Phediche and Bahunipati, in Nepal. Human faecal samples were collected from 241 participants, cultured using in vitro cultivation and examined for Blastocystis sp. The presence of Blastocystis sp. in faecal samples was further confirmed by polymerase chain reaction (PCR) and subsequently genotyped using subtype-specific sequence tagged site (STS) primers. There were 26.1% (63/241) of the participants that were infected by Blastocystis sp. We detected 84.1% (53/63) of Blastocystis sp. subtype 4 infections in these rural communities. The unusually high prevalence of Blastocystis sp. subtype 4 can be attributed to the rearing of family-owned animals in barns built close to their houses. Eighty one percent (51/63) of the Blastocystis sp. infected participants drank not boiled or unfiltered water. The present study revealed that Blastocystis sp. could pose a health concern to the communities and travellers to the hilly area in Nepal. Infection may be transmitted through human-to-human, zoonotic and waterborne transmissions. We provide recommendations to ensure good public health practices.
  15. Yusof A, Kumar S
    Parasitol Res, 2012 May;110(5):1823-8.
    PMID: 22076052 DOI: 10.1007/s00436-011-2705-9
    Trichomonas vaginalis, a flagellated protozoan parasite, is commonly found in the genitourinary tract of humans. Its mode of reproduction has always been reported to be binary fission. The high parasite numbers seen in a relatively short period in in vitro cultures led us to believe that there must be other modes of reproduction. The present study for the first time provides transformational evidence at the ultrastructural level seen in tropohozoites of T. vaginalis undergoing a multiple asexual mode of reproduction. The findings show that the single cell with a nucleus is capable of dividing to as many as eight nuclei within the cytoplasmic body. Before the commencement of division, the nucleus remained round or ovoid in shape with condensed chromatin masses and only a few endoplasmic reticula surrounding the nucleus. During the division, the nucleus started to elongate and become irregular in shape with visible chromatin masses condensing with the accumulation of numerous endoplasmic reticula. Nuclear division gave rise to as many as eight nuclei within a cell, which could be seen to be connected by numerous endoplasmic reticula. In addition, a high number of hydrogenosomes and vacuoles can be seen in multinucleated T. vaginalis compared with single nucleated T. vaginalis. This study confirms that multiple modes of nuclear division do exist in T. vaginalis and are a precursor to progeny formation.
  16. Wells K, Beaucournu JC, Durden LA, Petney TN, Lakim MB, O'Hara RB
    Parasitol Res, 2012 Aug;111(2):909-19.
    PMID: 22526293 DOI: 10.1007/s00436-012-2917-7
    Domestic dogs, Canis lupus, have been one of the longest companions of humans and have introduced their own menagerie of parasites and pathogens into this relationship. Here, we investigate the parasitic load of 212 domestic dogs with fleas (Siphonaptera) chewing lice (Phthiraptera), and ticks (Acarina) along a gradient from rural areas with near-natural forest cover to suburban areas in Northern Borneo (Sabah, Malaysia). We used a spatially-explicit hierarchical Bayesian model that allowed us to impute missing data and to consider spatial structure in modelling dog infestation probability and parasite density. We collected a total of 1,968 fleas of two species, Ctenocephalides orientis and Ctenocephalides felis felis, from 195 dogs (prevalence, 92 %). Flea density was higher on dogs residing in houses made of bamboo or corrugated metal (increase of 40 % from the average) compared to timber or stone/compound houses. Host-dependent and landscape-level environmental variables and spatial structure only had a weak explanatory power. We found adults of the invasive chewing louse Heterodoxus spiniger on 42 dogs (20 %). The effect of housing conditions was opposite to those for fleas; lice were only found on dogs residing in stone or timber houses. We found ticks of the species Rhipicephalus sanguineus as well as Haemaphysalis bispinosa gp., Haemaphysalis cornigera, Haemaphysalis koenigsbergi, and Haemaphysalis semermis on 36 dogs (17 %). The most common tick species was R. sanguineus, recorded from 23 dogs. Tick infestations were highest on dogs using both plantation and forest areas (282 % increase in overall tick density of dogs using all habitat types). The infestation probability of dogs with lice and ticks decreased with elevation, most infestations occurred below 800 m above sea level. However, the density of lice and ticks revealed no spatial structure; infestation probability of dogs with these two groups revealed considerable autocorrelation. Our study shows that environmental conditions on the house level appeared to be more influential on flea and lice density whereas tick density was also influenced by habitat use. Infestation of dogs with Haemaphysalis ticks identified an important link between dogs and forest wildlife for potential pathogen transmission.
  17. Afzan MY, Suresh K
    Parasitol Res, 2012 Jul;111(1):371-81.
    PMID: 22398830 DOI: 10.1007/s00436-012-2848-3
    Trichomonas vaginalis, a flagellated protozoan parasite causes a variety of adverse health consequences in both men and women. The parasite exists in the trophozoite and the pseudocystic stage. The study reports for the first time that pseudocyst forms of T. vaginalis isolated from cervical neoplasia (CN) patients demonstrated distinct, different and significant in vitro growth profiles when grown in vitro cultures from day 1 up to day 5 (p<0.05, Mann-Whitney test) when compared with the same life cycle stages isolated from non-cervical neoplasia but symptomatic patients (NCN). Pseudocysts from CN and NCN isolates remained viable in distilled water until 3 h 10 min and 2 h 10 min, respectively. The nucleus of pseudocysts in CN isolates using acridine orange and DAPI showed more intense staining revealing higher nuclear content. The FITC-labeled Concanavalin A stained stronger green fluorescence with surface of pseudocysts in CN isolates showing more rough and creased surface with higher numbers of deep micropores with larger numbers of chromatin masses, vacuoles, and hydrogenosomes. The study confirms that pseudocystic stage from CN, despite the uniformity in appearance of being rounded and showing no motility without a true cyst wall under light microscopy, demonstrated different biochemical, surface, and ultrastructural properties. The study provides evidence that phenotypic variant forms of pseudocysts does exist and possibly does play a role in exacerbating cervical cancer.
  18. Lau YL, Thiruvengadam G, Lee WW, Fong MY
    Parasitol Res, 2011 Sep;109(3):871-8.
    PMID: 21455621 DOI: 10.1007/s00436-011-2315-6
    In this study, we successfully expressed a chimerical surface antigen 1 and 2 (SAG1/2) of Toxoplasma gondii in Pichia pastoris. Eighty human serum samples, including 60 from confirmed cases of toxoplasmosis, were tested against the purified recombinant SAG1/2 in Western blots. Results of Western blots targeted at Toxoplasma IgG and IgM showed that the recombinant SAG1/2 reacted with all sera from the toxoplasmosis cases but none with the Toxoplasma-negative serum samples. These results showed that the P. pastoris-derived recombinant SAG1/2 was sensitive and specific and suitable for use as antigen for detecting anti-Toxoplasma antibodies. To further investigate the immunological characteristic of the recombinant protein, the recombinant SAG1/2 was injected subcutaneously into BALB/c mice, and their serum was tested against total protein lysate of T. gondii. Mice immunized with the recombinant SAG1/2 reacted specifically with the native SAG1 and SAG2 of T. gondii. Significant proliferation of splenocytes stimulated with tachyzoite total protein lysate was observed in vaccinated BALB/c mice but not in those from negative control mice. Specific production of IFN-γ, the Th1-type cytokines, was also found in stimulated splenocytes from vaccinated mice. These results show that the chimeric protein recombinant SAG1/2 can elicit a Th1-associated protection against T. gondii infections in mice. Finally, vaccinated mice were significantly protected against lethal challenge with live T. gondii RH strain tachyzoites (P 
  19. Nurul AA, Norazmi MN
    Parasitol Res, 2011 Apr;108(4):887-97.
    PMID: 21057812 DOI: 10.1007/s00436-010-2130-5
    Vaccine development against the blood-stage malaria parasite is aimed at reducing the pathology of the disease. We constructed a recombinant Mycobacterium bovis bacille Calmette Guerin (rBCG) expressing the 19 kDa C-terminus of Plasmodium falciparum merozoite surface protein-1 (MSP-1(19)) to evaluate its protective ability against merozoite invasion of red blood cells in vitro. A mutated version of MSP-1(19), previously shown to induce the production of inhibitory but not blocking antibodies, was cloned into a suitable shuttle plasmid and transformed into BCG Japan (designated rBCG016). A native version of the molecule was also cloned into BCG (rBCG026). Recombinant BCG expressing the mutated version of MSP-1(19) (rBCG016) elicited enhanced specific immune response against the epitope in BALB/c mice as compared to rBCG expressing the native version of the epitope (rBCG026). Sera from rBCG016-immunized mice contained significant levels of specific IgG, especially of the IgG2a subclass, against MSP-1(19) as determined by enzyme-linked immunosorbent assay. The sera was reactive with fixed P. falciparum merozoites as demonstrated by indirect immunofluorescence assay (IFA) and inhibited merozoite invasion of erythrocytes in vitro. Furthermore, lymphocytes from rBCG016-immunized mice demonstrated higher proliferative response against the MSP-1(19) antigen as compared to those of rBCG026- and BCG-immunized animals. rBCG expressing the mutated version of MSP-1(19) of P. falciparum induced enhanced humoral and cellular responses against the parasites paving the way for the rational use of rBCG as a blood-stage malaria vaccine candidate.
  20. Goh MY, Pan MZ, Blake DP, Wan KL, Song BK
    Parasitol Res, 2011 Mar;108(3):611-20.
    PMID: 20938684 DOI: 10.1007/s00436-010-2104-7
    Phosphatidylinositol 4-phosphate 5-kinase (PIP5K) may play an important role in host-cell invasion by the Eimeria species, protozoan parasites which can cause severe intestinal disease in livestock. Here, we report the structural organization of the PIP5K gene in Eimeria maxima (Weybridge strain). Two E. maxima BAC clones carrying the E. maxima PIP5K (EmPIP5K) coding sequences were selected for shotgun sequencing, yielding a 9.1-kb genomic segment. The EmPIP5K coding region was initially identified using in silico gene-prediction approaches and subsequently confirmed by mapping rapid amplification of cDNA ends and RT-PCR-generated cDNA sequence to its genomic segment. The putative EmPIP5K gene was located at position 710-8036 nt on the complimentary strand and comprised of 23 exons. Alignment of the 1147 amino acid sequence with previously annotated PIP5K proteins from other Apicomplexa species detected three conserved motifs encompassing the kinase core domain, which has been shown by previous protein deletion studies to be necessary for PIP5K protein function. Phylogenetic analysis provided further evidence that the putative EmPIP5K protein is orthologous to that of other Apicomplexa. Subsequent comparative gene structure characterization revealed events of intron loss/gain throughout the evolution of the apicomplexan PIP5K gene. Further scrutiny of the genomic structure revealed a possible trend towards "intron gain" between two of the motif regions. Our findings offer preliminary insights into the structural variations that have occurred during the evolution of the PIP5K locus and may aid in understanding the functional role of this gene in the cellular biology of apicomplexan parasites.
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