Alternative migration routes of Ascaris suum in the pig

Domain definition and preliminary functional exploration of the endonuclease NOBP-1 in Strongyloides stercoralis

BACKGROUND

Ribosome biogenesis is the process of assembling ribosome complexes that regulate cell proliferation and differentiation with potential regulatory effects on development. Many factors regulate ribosome biological processes. Nin one binding protein (Nob1) has received widespread attention as key genes regulating ribosome biogenesis-the 3' end of the 20S rRNA is cleaved by Nob1 at cleavage site D to form 18S rRNA, generating translationally capable 40S subunit. As a ribosome biogenesis factor, Nob1 may regulate the development of organisms, but almost nothing is known about the function of Nob1 for any parasitic nematode. We explored the functional role of NOBP-1 (the homologous gene of Nob1) encoding gene from a parasitic nematode-Strongyloides stercoralis.

METHODS

The full-length cDNA, gDNA and promoter region of Ss-nobp-1 was identified using protein BLAST in WormBase ParaSite according to the Caenorhabditis elegans NOBP-1 sequence to analyze the gene structure. RNA sequencing (RNA-seq) data in wormbase were retrieved and analyzed to assess the transcript abundance of Ss-nobp-1 in seven developmental stages of S. stercoralis. The standard method for gonadal microinjection of constructs was carried out to determine the anatomic expression patterns of Ss-nobp-1. The interaction between Ss-NOBP-1 and partner of NOBP-1 (Ss-PNO-1) was assessed by yeast two-hybridization and bimolecular fluorescence complementarity (BiFC) experiments.

RESULTS

The NOBP-1 encoding gene Ss-nopb-1 from the zoonotic parasite S. stercoralis has been isolated and characterized. The genomic DNA representing Ss-nobp-1 includes a 1599-bp coding region and encodes a protein comprising 403 amino acids (aa), which contains conserved PIN domain and zinc ribbon domain. RNA-seq analysis revealed that Ss-nobp-1 transcripts are present throughout the seven developmental stages in S. stercoralis and have higher transcription levels in iL3, L3 and P Female. Ss-nobp-1 is expressed mainly in the intestine of transgenic S. stercoralis larvae, and there is a direct interaction between Ss-NOBP-1 and Ss-PNO-1.

CONCLUSIONS

Collectively, Ss-NOBP-1 has a potential role in embryo formation and the infective process, and findings from this study provide a sound foundation for investigating its function during the development of parasitic nematode.

Pulmonary Computed Tomography Findings of Visceral Larva Migrans Caused by Ascaris suum

OBJECTIVE

To retrospectively evaluate the computed tomography (CT) findings of pulmonary involvement in patients with visceral larva migrans caused by Ascaris suum.

METHODS

Institutional review board approval was obtained, and informed consent was waived. Chest CT scans obtained between January 1994 and November 2005 in 32 patients infected with A. suum were retrospectively evaluated by 3 chest radiologists. In 4 patients who underwent surgical or transbronchial biopsy, comparisons of the CT images with the actual specimens were performed.

RESULTS

On CT scans, abnormal findings were seen in 28 patients. The most common abnormality consisted of nodules (n = 19) in which the majority had a halo of ground-glass attenuation (n = 17), followed by ground-glass attenuation (n = 18), and interlobular septal thickening (n = 14). These abnormalities were predominantly seen in the peripheral lung (n = 25). Of the 7 patients who underwent follow-up CT scans, nodules (n = 6) and ground-glass attenuation (n = 5) had migrated in 4 patients. Pathologically, these findings corresponded to marked eosinophilic infiltration into the interstitium.

CONCLUSIONS

These CT findings are considered to be suggestive of thoracic involvement in patients with visceral larva migrans caused by A. suum.

Diagnosis of parasitic zoonoses by immunoenzymatic assays--analysis of cross-reactivity among the excretory/secretory antigens of Fasciola hepatica, Toxocara canis, and Ascaris suum

Several parasitic infections such fasciolosis, toxocariosis or ascariosis are important zoonoses. During the infection with Fasciola hepatica, Toxocara canis and Ascaris suum, an important intraorganic phase in their hosts takes place, releasing antigens responsible for a humoral immune response, which enables the diagnosis of that parasitosis. A study to identify the existence of cross-reactivity among the excretory/ secretory antigens of F. hepatica, T. canis and A. suum was developed. One group of Sprague-Dawley rats was infected with 20 metacercariae of F. hepatica and another group remained uninfected as control. By means of an Indirect-ELISA, the rat humoral immune response (IgG and IgM) against the excretory/secretory antigens of F. hepatica was analysed and measured for cross reactivity with T. canis and A. suum. IgM cross-reaction was mainly observed in the first 10 weeks post-infection. IgG cross-reaction was observed throughout the study, and was maximal at the 2-3 weeks and 3-6 weeks post-infection, which corresponds to the intraorganic migratory phase of these parasites. The western-blot showed that the rat IgG recognised three proteins of 190, 160 and 33 kDa in the antigens from F. hepatica, T. canis and A. suum. The existence of cross-reactivity among these antigens seems to demonstrate also the presence of structural similarities, such as tegumental proteins. These results should be consider when immunoassay probes are used in the diagnosis of parasitic infections.