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The Qinghai–Tibet Plateau Area (QTPA) has a complex natural ecosystem, causing a greatly increased risk of spreading various tick-borne diseases including rickettsial infections, which are regarded as one of the oldest known vector-borne zoonoses. However, the information of one of its pathogen, spotted fever group Rickettsia (SFG Rickettsia ), is limited in tick vectors and animals in this area. Therefore, this study focused on the investigation of SFG Rickettsia in tick vectors, yaks ( Bos grunniens ), and Tibetan sheep ( Ovis aries ) in the QTPA. A total of 1,000 samples were collected from nine sampling sites, including 425 of yaks, 309 of Tibetan sheep, 266 of ticks. By morphological examination, PCR, and sequencing, we confirmed the species of all collected ticks. All tick samples, all yak and Tibetan sheep blood samples were detected based on SFG Rickettsia ompA and sca4 gene. The results showed that all tick samples were identified to be Haemaphysalis qinghaiensis , and the positive rates of SFG Rickettsia were 5.9% (25/425), 0.3% (1/309), and 54.1% (144/266) in yaks, Tibetan sheep, and ticks, respectively. All positive samples were sequenced, and BLASTn analysis of the ompA gene sequences of SFG Rickettsia showed that all positive samples from animals and ticks had 99.04–100% identity with yak and horse isolates from Qinghai Province, China. BLASTn analysis of the sca4 gene sequences of SFG Rickettsia showed that all positive samples had 97.60–98.72% identity with tick isolates from Ukraine. In addition, the phylogenetic analysis showed that all the SFG Rickettsia ompA and sca4 sequences obtained from this study belong to the same clade as Rickettsia raoultii isolated from livestock and ticks from China and other countries. Molecularly, this study detected and characterized SFG Rickettsia both in the tick vectors and animals, suggesting that the relationship between SFG Rickettsia , tick species and animal hosts should be explored to understand their interrelationships, which provide a theoretical basis for preventing control of this pathogen.

Melophagus ovinus (sheep ked) is a hematophagous ectoparasite that mainly parasitizes sheep. In addition to causing inflammation, wool loss, and skin damage to the animal hosts, M. ovinus also serves as a vector for a variety of pathogens and is highly likely to participate in the life and transmission cycle of pathogenic organisms. Herein, we investigated the presence and molecular characterization of vector-borne pathogens in M. ovinus from Qinghai-Tibet Plateau, China. A total of 92 M. ovinus pools collected from the Qinghai province of China were screened for the presence of selected vector-borne pathogens. The overall positive rate of A. ovis, A. bovis, A. phagocytophilum, and T. ovis in M. ovinus was 39.1%, 17.4%, 9.8%, and 89.1%, respectively. All of the samples were negative for Border disease virus (BDV), other Anaplasma species, Babesia spp., Rickettsia spp., and Borrelia spp. Co-infection of different Anaplasma species and T. ovis occurred in 51.2% of all samples with T. ovis. The positive rates of A. ovis, A. bovis, and A. phagocytophilum in different regions and altitudes of the sampling sites were significantly different. Sequence and phylogenetic analysis of target genes confirmed their identity with corresponding pathogens. Our results elucidate the occurrence and molecular characterization of Anaplasma spp. and Theileria spp. in M. ovinus, which could act as potential zoonotic reservoirs. To the best of our knowledge, this is the first report of the detection of A. bovis and A. phagocytophilum DNA in M. ovinus. This study gives the first extensive molecular survey of vector-borne pathogens with veterinary and public health significance in M. ovinus from the Qinghai-Tibet Plateau, China.

Avain influenza (AI) virus H5N1 poses a serious threat to public health. Yamanaka factors (Oct4, Sox2, Klf4, c-Myc) are usually transcription factors involved in proliferation, apoptosis, differentiation, immunity and somatic cell reprogramming. However, the expression status of Yamanaka factors related to influenza virus infection has not yet been described. Here our results showed that SOX2, MYC and KLF4 were significantly overexpressed in HEK293T cells as compared to A549 cells. The H5N1 virus infection experiment showed that OCT4 and KLF4 were up-regulated and MYC was down-regulated during high titer virus infection in A549 cells. In HEK293T cells, OCT4, SOX2 and KLF4 were up-regulated and MYC was down-regulated by H5N1 infection. Overexpression of NP and PB2 of H5N1 virus induced up-regulation of OCT4 in A549 cells. In addition, KF4 was increased only by overexpression of NP protein in A549 cells. However, KLF4 was down-regulated by overexpression of PB2 protein in HEK293T cells. Yamanaka factors were not found to be significantly affected by NS1 and M1 in A549 and HEK293T cells. HA or NA did not affect the expression of Yamanaka factors in HEK293T cells. In conclusion, the expression patterns of Yamanaka factors during H5N1 infection could be a novel regulatory mechanism involved in the pathogenesis of influenza viruses.

The aim of this work was a preliminary study on the immunogenicity and protectivity effect of eukaryotic and prokaryotic expressed M2e-Carliticulin (CRT) in the experimental mice. We constructed and expressed M2e-CRT in and . Then we evaluated the immunological responses and virus challenge following injection of M2e-CRT fusion protein, expressed in and as a recombinant protein vaccine. According to this issue, a prime-boost administration of M2e-CRT by subcutaneous route in C57Bl/6 mouse model was done. Both fusion proteins induced comparable immunologic responses. But because of easier and cheaper purification in prokaryote system this has led to the M2e-CRT as a vaccine candidate in prokaryote system compared with eukaryotic is preferred.

We tested the ability of retrocyclin 2, a type of θ defensin, to protect cells and chicken embryos from infection by H5N1 highly pathogenic avian influenza virus. A gene fragment of retrocyclin 2 was designed based on the protein sequence of retrocyclin 2 and cloned into the eukaryotic expression vector pcDNA4.01 (HismaxA), named pcDNA4-RC2. The expression vector pcDNA4-RC2 protected MDCK cells and chicken embryos from infection by the H5N1 virus through inhibition of virus replication and viral mRNA transcription. Retrocyclin 2 is therefore effective in preventing H5N1 virus infection in vivo and in vitro and could be considered as a new therapy for H5N1 influenza and other diseases.

The gut microbiota significantly influences host physiology and provides essential ecosystem services. While diet can affect the composition of the gut microbiota, the gut microbiota can also help the host adapt to specific dietary habits. The carrion crow (Corvus corone), an urban facultative scavenger bird, hosts an abundance of pathogens due to its scavenging behavior. Despite this, carrion crows infrequently exhibit illness, a phenomenon related to their unique physiological adaptability. At present, however, the role of the gut microbiota remains incompletely understood. In this study, we performed a comparative analysis using 16S rRNA amplicon sequencing technology to assess colonic content in carrion crows and 16 other bird species with different diets in Beijing, China. Our findings revealed that the dominant gut microbiota in carrion crows was primarily composed of Proteobacteria (75.51%) and Firmicutes (22.37%). Significant differences were observed in the relative abundance of Enterococcus faecalis among groups, highlighting its potential as a biomarker of facultative scavenging behavior in carrion crows. Subsequently, E. faecalis isolated from carrion crows was transplanted into model mice to explore the protective effects of this bacterial community against Salmonella enterica infection. Results showed that E. faecalis down-regulated the expression of pro-inflammatory cytokines tumor necrosis factor alpha (TNF-α), interferon gamma (IFN-γ), and interleukin 6 (IL-6), prevented S. enterica colonization, and regulated the composition of gut microbiota in mice, thereby modulating the host's immune regulatory capacity. Therefore, E. faecalis exerts immunoregulatory and antipathogenic functions in carrion crows engaged in scavenging behavior, offering a representative case of how the gut microbiota contributes to the protection of hosts with specialized diets.

Objective: Our aim was to reveal the molecular characteristics of human H1N1 influenza virus hemagglutinin (HA) genes from 1947 to 2009 in China. Methods: 129 HA gene sequences were downloaded from NCBI’s GenBank and analyzed by DNASTAR software. Additionally, the three-dimensional structure of HA protein was predicted by the SWISS-MODEL service. Results: First, 2009 Chinese HA genes were 99% identical to those of Mexican and American ones; their key sites remained highly conserved. Second, 50 Chinese strains from 1947 to 2009 clustered by the year of isolation, and 2009 strains had only 70% identity to 1947–2008 ones. Third, over the past 60 years, 3 receptor-binding (RB) sites and 2 of the 8 glycosylation sites (amino acids 279 and 290) underwent considerable changes while the cleavage sites remained stable. Fourth, the human HA sequences differed completely from swine and avian isolates. Finally, the mutation of cleavage sites can change the three-dimensional structures, but single mutations cannot. Conclusions: Thus, in the past 60 years, Chinese H1N1 influenza HA genes kept stable with high affinity and low pathogenicity to human except changes in 2 glycosylation and 3 RB sites which were associated with the pandemic strength, range and host specificity of viruses.

Various thymic peptides (including thymulin, thymic humoral factor, thymopoietin, etc.) play important roles in the process of T cell maturation and development. We isolated a new peptide from calf thymus and named it thymus activity factor II (TAF-II). A yield of 0.92 mg of TAF-II was purified from 500 g calf thymus. Analysis by LC/MSD-Trap showed the amino acid sequence of this hexapeptide to be Glu-Ala-Lys-Ser-Gln-Gly-OH with molecular weight 618.5 daltons. We have also begun to investigate the influence of TAF-II.

To accurately determine the expression and distribution patterns of two infuenza virus receptors （SAa2,3-gal and SAa2,6-gal） in trachea and lung tissues of humans, mice, chickens and ducks, we analyzed lectin immunofluorescence stainings of various tissue sections qualitatively and quantitatively. Results from the qualitative analysis showed that both influenza virus receptors were expressed in lung tissues of humans, mice, chickens and ducks as well as trachea tissues of mice and ducks. However, SAa2,6-gal receptor was expressed only in the human trachea tissue and SAa2,3-gal receptor was expressed only in the chicken trachea tissue. Results from the quantitative analysis demonstrated that both receptors were expressed in trachea tis- sues of human and mouse, as well as in lung tissues of humans, chickens and ducks. Meanwhile, our results also showed that the expression and distribution of influenza virus receptors in the same tissue were not always uniform, indicating that their distribution and expression in various tissues are not simply the distinction between the presence or absence of receptors, but rather the difference in the amount of expressed receptors.

Haemosporidians are vector-transmitted intracellular parasites that happen in numerous bird species worldwide and may possibly have important effects for wild bird populations. Studies of haemosporidians most dedicated on Europe and North America, and only newly some study in the Neotropics has been done, where the occurrence and influences of the disease have been less considered and are not understood well. In this study we designed a study in the nestling birds of prey in Mongolia. We sampled blood from 72 raptors at 2 different species and evaluated avian haemosporidian infection by two nested PCR protocol and one Real time PCR protocol. Sequencing a portion of the cytochrome b (cyt b) gene of the parasite. From the sampled birds, 10 % were infected by Plasmodium. Inclusive, our findings advocate a high haemosporidian species richness in the bird community of Mongolia. In view of the frequency of local habitat loss that in this area is living, recognize how avian haemosporidians affect bird populations it is very important; in addition, more exhaustive sampling is required to fully understand the range of avian haemosporidian infection in this area.