Objective To investigate the prevalence of Bartonella infection and gene polymorphisms of Bartonella in small mammals in Maixiu National Forest Park in the Qinghai-Tibet Plateau, China, and to provide a scientific basis for the control and prevention of local natural focal diseases. Methods The night trapping method was used to capture small mammals, whose liver and spleen tissues were collected and cultured for Bartonella isolation. The suspected positive colonies were confirmed using PCR amplification and sequencing of the citrate synthase ( gltA) gene. BLAST and MEGA 7.0 softwares were used to perform the nucleotide sequence homology comparison and phylogenetic analysis, and DnaSP 5.10 software was used to analyze the genetic diversity. Results A total of 21 rodents were captured, including 10 Cricetulus longicaudatus rodents, 6 Apodemus speciosus rodents, 4 Mus musculus rodents, and 1 Microtus oeconomus rodent. In addition, one small mammal of Soricidea, which belonged to Insectivora, was also captured. Except M. oeconomus, Bartonella was detected in all the other four species of small mammals, with an overall positive rate of 59.09% (13/22). Specifically, nine cases showed positive results in both the liver and spleen tissues, one showed positive results in the liver tissue alone, and three showed positive results in the spleen tissue alone. There was no statistical difference in the positive rate between liver and spleen tissues (45.45% vs 54.55%, P=0.625). The phylogenetic analysis showed that the isolated Bartonella species were as follows: Bartonella grahamii (10 strains), B. taylorii (1 strain), B. khabarovsk (1 strain), and B. japonica (1 strain), among which B. grahamii was the dominant prevalent species with potential pathogenicity. In addition, the traceability analysis showed that the B. grahamii isolates from C. longicaudatus and M. musculus belonged to the same cluster as those from A. speciosus in Japan, and the B. grahamii isolates from A. speciosus belonged to the same cluster as those from Ochotona curzoniae in this area. The genetic diversity analysis showed that the nucleotide sequences in B. grahamii were quite different between various rodent species. There were 8 polymorphic loci in the 10 sequences, resulting in 3 haplotypes. The haplotype diversity (Hd) was 0.622±0.138; the average number of nucleotide differences (k) was 3.200, and the nucleotide diversity ( π) was 0.010. The fragment diversity was highest between 152 bp and 251 bp. Conclusion The small mammals in Maixiu National Forest Park have a high infection rate with Bartonella, and B. grahamii is the dominant species, which has genetic diversity and may cause human infection and diseases.

【Abstract】 Objective To observe the injury of the antimicrobial peptides with anti-Toxoplasma activity isolated from housefly larvae on the DNA of T.gondii tachyzoites. Methods The antimicrobial peptides of housefly larvae were induced largely by infection and injury, which were isolated and purified by trituration, centrifugalization and column chromatography. Then the antimicrobial peptides with anti-Toxoplasma activity were sieved by methyl thiazolyl tetrazolium colorimetric method and haemacytometry. The DNA contents of T.gondii tachyzoites were detected by flow cytometry （FCM）.  Results From the bar chart of DNA contents, it showed that the difference of distribution between the control group and the experimental group, and tachyzoites in the experimental group were fewer than that in the control group. The tachyzoites in M1 phase were fewer than that in M2 phase in the control group, but the condition was on the contrary in the antimicrobial peptide group. Furthermore, the peak in the M1 stage had an obvious antedisplacement.  Conclusion The antimicrobial peptide isolated from housefly larvae could kill T.gondii by inhibiting the synthesis of DNA.

Objective Isolate and purify the antimicrobial peptides with anti- Toxoplasma activity from the haemlymph of Musca domestica pupa. Methods The antimicrobial peptide of M.domestica pupa were produced largely by infection and injury,which were isolated and purified by trituration, centrifugalization and column chromatography of AKTA ^TM purifier. Then the antimicrobial peptides with anti- Toxoplasma activity were selected by haemacytometry and MTT colorimetric method. Results It was found that there was a ultraviolet absorption peak at 280 nm when retention volume was 9.4 ml through Resource S cationic exchange column chromatography, which had anti- Toxoplasma activity. This protein was collected and purified further with Superdex G75 gel column chromatography. And there were six ultraviolet absorption peaks at 280 nm through Superdex G75 gel column chromatography, and the sixth one had anti- Toxoplasma activity. Conclusion There was an antimicrobial peptide with anti- Toxoplasma activity in the haemlymph of M.domestica pupa.