iTRAQ-Based Phosphoproteomic Analysis Exposes Molecular Changes in the Small Intestinal Epithelia of Cats after Toxoplasma gondii Infection.

Toxoplasma gondii, an obligate intracellular parasite, has the ability to invade and proliferate within most nucleated cells. The invasion and destruction of host cells by T. gondii lead to significant changes in the cellular signal transduction network. One important post-translational modification (PTM) of proteins is phosphorylation/dephosphorylation, which plays a crucial role in cell signal transmission. In this study, we aimed to investigate how T. gondii regulates signal transduction in definitive host cells. We employed titanium dioxide (TiO2) affinity chromatography to enrich phosphopeptides in the small intestinal epithelia of cats at 10 days post-infection with the T. gondii Prugniuad (Pru) strain and quantified them using iTRAQ technology. A total of 4998 phosphopeptides, 3497 phosphorylation sites, and 1805 phosphoproteins were identified. Among the 705 differentially expressed phosphoproteins (DEPs), 68 were down-regulated and 637 were up-regulated. The bioinformatics analysis revealed that the DE phosphoproteins were involved in various cellular processes, including actin cytoskeleton reorganization, cell necroptosis, and MHC immune processes. Our findings confirm that T. gondii infection leads to extensive changes in the phosphorylation of proteins in the cat intestinal epithelial cells. The results of this study provide a theoretical foundation for understanding the interaction between T. gondii and its definitive host.

Prevalence and multilocus genotyping of Giardia duodenalis in zoo animals in three cities in China.

Giardia duodenalis is a flagellated parasitic microorganism that parasitizes in the intestines of humans and animals. Although asymptomatic infections commonly exist in both humans and animals, some enteric symptoms have been reported in immunocompromised individuals, posing a threat to public health. Children could be infected with G. duodenalis through an environment contaminated by infective animals. Thus, the investigation of the prevalence and genotypes of G. duodenalis in zoo animals is important. In this study, 672 fecal samples of 113 species of animals, including non-human primates, artiodactyla, perissodactyla, proboscidian, marsupial, birds, carnivora, and rodents, were collected from three zoos in Hangzhou city, Dalian city, and Suzhou city in China. The samples were screened for the positivity of G. duodenalis by nested PCR based on the ß-giardin (bg), triosephosphate isomerase (tpi), and glutamate dehydrogenase (gdh) gene loci. The overall G. duodenalis prevalence was 10.6% (71/672). The prevalence in non-human primates, artiodactyla, perissodactyla, proboscidian, marsupial, birds, carnivora, and rodent was 6.9% (10/144), 9.0% (12/133), 17.1% (6/35), 0% (0/6), 8.7% (2/23), 13.3% (28/211), 6.7% (7/105), and 40.0% (6/15), respectively. The region and category were considered risk factors for G. duodenalis infection in zoo animals (p < 0.001). Additionally, four genotypes of G. duodenalis were identified in zoo animals, including assemblage E (n = 46), assemblage A (n = 18), assemblage B (n = 6), and assemblage D (n = 1). The assemblages A, B, D, and E are also genotypes observed in humans and other animals. Among the sequences obtained in our study, one multilocus genotype (MLG) of the sub-assemblage AI was observed within assemblage A. Furthermore, three MLGs were detected within assemblage B. These findings reveal G. duodenalis genetic variability in zoo animals in three cities in China and suggest that zoo animals could be a potential source of human infection with G. duodenalis.

Acetylome analysis of the feline small intestine following Toxoplasma gondii infection.

Toxoplasma gondii is a protozoan parasite capable of infecting a large number of warm-blooded animals and causes serious health complications in immunocompromised patients. T. gondii infection of the feline small intestine is critical for the completion of the life cycle and transmission of T. gondii. Protein acetylation is an important posttranslational modification, which plays roles in the regulation of various cellular processes. Therefore, understanding of how T. gondii reprograms the protein acetylation status of feline definitive host can help to thwart the production and spread of T. gondii. Here, we used affinity enrichment and high-resolution liquid chromatography with tandem mass spectrometry to profile the alterations of the acetylome in cat small intestine 10 days after infection by T. gondii Prugniuad (Pru) strain. Our analysis showed that T. gondii induced significant changes in the acetylation of proteins in the cat intestine. We identified 2606 unique lysine acetylation sites in 1357 acetylated proteins. The levels of 334 acetylated peptides were downregulated, while the levels of 82 acetylated peptides were increased in the infected small intestine. The proteins with differentially acetylated peptides were particularly enriched in the bioenergetics-related processes, such as tricarboxylic acid cycle, oxidative phosphorylation, and oxidation-reduction. These results provide the first baseline of the global acetylome of feline small intestine following T. gondii infection and should facilitate further analysis of the role of acetylated protein in the pathogenesis of T. gondii infection in its definitive host.

Prevalence and subtypes of Blastocystis sp. infection in zoo animals in three cities in China.

Blastocystis is a highly prevalent eukaryotic parasite of many animals and humans worldwide. It can compromise the gastrointestinal tract and cause gastrointestinal symptoms, constituting a serious threat to human health and animal growth. Many animals are potential sources of Blastocystis infection in humans. However, limited data are available regarding the prevalence and subtype distribution of Blastocystis infection among zoo animals in China. Therefore, the present study examined the prevalence and subtypes of Blastocystis in zoo animals in Hangzhou, Dalian, and Suzhou cities, China. Of 450 fecal samples from zoo animals, 27 (6.0%) were PCR-positive for Blastocystis, with 7.7% (8/104), 11.3% (7/62), 16.7% (3/18), 1.8% (2/114), 6.3% (1/16), 9.5% (2/21), and 3.6% (4/109) in artiodactyla, aves, rodentia, nonhuman primates, perissodactyla, marsupialia, and carnivora, respectively. Significant differences in the prevalence of Blastocystis were found among different animal groups (P < 0.05). Sequence analysis showed 7 known subtypes (ST2, ST4, ST5, ST7, ST8, ST10, and ST14) of Blastocystis in the present study, with ST10 (10/27) as the predominant subtype in all three of the examined zoos. To our knowledge, this is the first report of Blastocystis infection in Damaliscus dorcas, Cervus elaphus, Macropus rufogriseus, Grus japonensis, Trichoglossus haematodus, Panthera tigris ssp. tigris (white), Panthera tigris ssp. altaica, Lycaon pictus, Suricata suricatta, and Dolichotis patagonum in China. These results demonstrate the presence of Blastocystis infection in zoo animals and provided baseline data for preventing and controlling Blastocystis infection in zoo animals and humans in China.