Genetic characterization of Toxoplasma gondii from domestic animals in central China.

Toxoplasma gondii is an obligate intracellular parasite that has a remarkable ability to infect almost all warm-blooded animals, including humans. This study was aimed to determine the genetic characteristics of T. gondii isolates from domestic animals in Henan Province, central China. A total of 363 DNA samples, including 208 from hilar lymph nodes of pigs, 36 from blood samples of cats, 12 from tissues of aborted bovine fetuses and 107 from blood samples of dams with history of abortion in Henan Province, were examined for the presence of T. gondii by nested PCR based on B1 gene. The positive DNA samples were further genotyped by PCR-RFLP at 11 markers, including SAG1, (3'+ 5') SAG2, alt.SAG2, SAG3, BTUB, GRA6, c22-8, c29-2, L358, PK1, and Apico. DNA samples from 9 pigs, 5 cats, and 4 dairy cows were T. gondii B1 gene positive. Nine samples were successfully genotyped at all genetic loci, of which 5 samples from pigs, and 2 from cats were identified as ToxoDB genotype #9, and 2 samples from cows belonged to ToxoDB genotype #225. To our knowledge, the present study is the second report of genetic typing of T. gondii isolates from cattle in China, and the first report of T. gondii ToxoDB#225 from cattle.

Genetic characterization of Toxoplasma gondii from domestic animals in central China

Toxoplasma gondii is an obligate intracellular parasite that has a remarkable ability to infect almost all warm-blooded animals, including humans. This study was aimed to determine the genetic characteristics of T. gondii isolates from domestic animals in Henan Province, central China. A total of 363 DNA samples, including 208 from hilar lymph nodes of pigs, 36 from blood samples of cats, 12 from tissues of aborted bovine fetuses and 107 from blood samples of dams with history of abortion in Henan Province, were examined for the presence of T. gondii by nested PCR based on B1 gene. The positive DNA samples were further genotyped by PCR-RFLP at 11 markers, including SAG1, (3’+ 5’) SAG2, alt.SAG2, SAG3, BTUB, GRA6, c22-8, c29-2, L358, PK1, and Apico. DNA samples from 9 pigs, 5 cats, and 4 dairy cows were T. gondii B1 gene positive. Nine samples were successfully genotyped at all genetic loci, of which 5 samples from pigs, and 2 from cats were identified as ToxoDB genotype #9, and 2 samples from cows belonged to ToxoDB genotype #225. To our knowledge, the present study is the second report of genetic typing of T. gondii isolates from cattle in China, and the first report of T. gondii ToxoDB#225 from cattle.

Inhibition of STAT3 by RNA interference suppresses angiogenesis in colorectal carcinoma

In order to investigate signal transduction and activation of transcription 3 (STAT3) signaling on angiogenesis in colorectal carcinoma (CRC) after inhibiting STAT3 expression, we constructed the HT-29-shSTAT3 cell line by lentivirus-mediated RNAi. Cell growth was assessed with MTT and the cell cycle distribution by flow cytometry. CRC nude mouse models were established and tumor growth was monitored periodically. On day 30, all mice were killed and tumor tissues were removed. Microvessel density (MVD) was determined according to CD34-positive staining. The expression of vascular endothelial growth factor A (VEGFA), matrix metalloproteinase-2 (MMP2) and basic fibroblast growth factor (FGF2) was monitored by quantitative real-time PCR and Western blot analysis. Knockdown of STAT3 expression significantly inhibited cell growth in HT-29 cells, with a significantly higher proportion of cells at G0/G1 (P < 0.01). Consistently, in vivo data also demonstrated that tumor growth was significantly inhibited in mice injected with HT-29-shSTAT3 cells. MVD was 9.80 ± 3.02 in the HT-29-shSTAT3 group, significantly less than that of the control group (P < 0.01). mRNA and protein levels of VEGFA and MMP2 in the HT-29-shSTAT3 group were significantly lower than in the control group (P < 0.05), but no significant difference was observed in the mRNA or protein level of FGF2 (P > 0.05). Taken together, these results demonstrate that STAT3 signaling is important to the growth of CRC and promotes angiogenesis by regulating VEGFA and MMP2 expression.

Inhibition of STAT3 by RNA interference suppresses angiogenesis in colorectal carcinoma.

In order to investigate signal transduction and activation of transcription 3 (STAT3) signaling on angiogenesis in colorectal carcinoma (CRC) after inhibiting STAT3 expression, we constructed the HT-29-shSTAT3 cell line by lentivirus-mediated RNAi. Cell growth was assessed with MTT and the cell cycle distribution by flow cytometry. CRC nude mouse models were established and tumor growth was monitored periodically. On day 30, all mice were killed and tumor tissues were removed. Microvessel density (MVD) was determined according to CD34-positive staining. The expression of vascular endothelial growth factor A (VEGFA), matrix metalloproteinase-2 (MMP2) and basic fibroblast growth factor (FGF2) was monitored by quantitative real-time PCR and Western blot analysis. Knockdown of STAT3 expression significantly inhibited cell growth in HT-29 cells, with a significantly higher proportion of cells at G0/G1 (P < 0.01). Consistently, in vivo data also demonstrated that tumor growth was significantly inhibited in mice injected with HT-29-shSTAT3 cells. MVD was 9.80 ± 3.02 in the HT-29-shSTAT3 group, significantly less than that of the control group (P < 0.01). mRNA and protein levels of VEGFA and MMP2 in the HT-29-shSTAT3 group were significantly lower than in the control group (P < 0.05), but no significant difference was observed in the mRNA or protein level of FGF2 (P > 0.05). Taken together, these results demonstrate that STAT3 signaling is important to the growth of CRC and promotes angiogenesis by regulating VEGFA and MMP2 expression.

Detection of Neospora caninum in aborted bovine fetuses and dam blood samples by nested PCR and ELISA and seroprevalence in Beijing and Tianjin, China.

Neospora caninum infection is a significant cause of abortion in cattle. We investigated the tissue distribution of N. caninum in aborted bovine fetuses and dam blood samples by a nested PCR assay, and compared the nested PCR with ELISA in the diagnosis of N. caninum infection. In total, 26 aborted fetuses and 813 blood samples were collected from 8 dairy herds in Beijing (n=212) and Tianjin (n=601), China. Fifteen fetuses (57.7%) were tested N. caninum-positive by the nested PCR. N. caninum DNA was detected from the brain of 52%, kidneys of 22%, skeletal muscle of 18%, and heart of 4% of the aborted fetuses. The PCR-positive cases (55%, 11/20) were higher than seropositive cows (40%, 8/20) in a subset of 20 fetuses, but the PCR results of blood samples of the 20 cows were all negative. The seroprevalence of the 813 samples was 15.5% (43.4% of samples from Beijing, 5.7% of samples from Tianjin), compared to the PCR-positive blood samples of 0.9%. Our study showed that the nested PCR is a valuable diagnostic tool for the primary diagnosis of N. caninum in aborted fetuses, while ELISA is the preferred assay for testing blood samples collected from cows. The two assays are complementary in determining whether abortions are associated with N. caninum infection in cattle.