Large-Scale Comparative Analyses of Tick Genomes Elucidate Their Genetic Diversity and Vector Capacities.

Among arthropod vectors, ticks transmit the most diverse human and animal pathogens, leading to an increasing number of new challenges worldwide. Here we sequenced and assembled high-quality genomes of six ixodid tick species and further resequenced 678 tick specimens to understand three key aspects of ticks: genetic diversity, population structure, and pathogen distribution. We explored the genetic basis common to ticks, including heme and hemoglobin digestion, iron metabolism, and reactive oxygen species, and unveiled for the first time that genetic structure and pathogen composition in different tick species are mainly shaped by ecological and geographic factors. We further identified species-specific determinants associated with different host ranges, life cycles, and distributions. The findings of this study are an invaluable resource for research and control of ticks and tick-borne diseases.

Spatial risk of Haemaphysalis longicornis borne Dabieshan tick virus (DBTV) in China.

The uncertainty and unknowability of emerging infectious diseases have caused many major public health and security incidents in recent years. As a new tick-borne disease, Dabieshan tick virus (DBTV) necessitate systematic epidemiological and spatial distribution analysis. In this study, tick samples from Liaoning Province were collected and used to evaluate distribution of DBTV in ticks. Outbreak points of DBTV and the records of the vector Haemaphysalis longicornis in China were collected and used to establish a prediction model using niche model combined with environmental factors. We found that H. longicornis and DBTV were widely distributed in Liaoning Province. The risk analysis results showed that the DBTV in the eastern provinces of China has a high risk, and the risk is greatly influenced by elevation, land cover, and meteorological factors. The risk geographical area predicted by the model is significantly larger than the detected positive areas, indicating that the etiological survey is seriously insufficient. This study provided molecular and important epidemiological evidence for etiological ecology of DBTV. The predicted high-risk areas indicated the insufficient monitoring and risk evaluation and the necessity of future monitoring and control work.

Clinical and etiological characteristics of severe hemorrhagic fever caused by coinfection of hantaan orthohantavirus and severe fever with thrombocytopenia syndrome virus.

Severe fever with thrombocytopenia syndrome (SFTS) and hemorrhagic fever with renal syndrome (HFRS) usually have different infection routes, and coinfection is relatively rare. This study examines the clinical and etiological characteristics of coinfection by these two pathogens to provide important references for clinical diagnosis and treatment. Blood samples from 22 clinically diagnosed patients with HFRS were collected for molecular detection of HFRS and common tick and mouse borne diseases. Inoculate the blood of six severe and critically patients into cells to isolate and proliferate potential viruses, and retest the cell culture to determine the pathogen. In addition, complete data were collected from these 22 HFRS and concurrent SFTS patients, and white blood cells (WBCs), platelet (PLT), blood urea nitrogen (BUN), creatinine (Cr) and other data were compared and analyzed. A total of 31 febrile patients, including 22 HFRS patients and 9 SFTS patients, were collected from September 2021 to October 2022. Among these HFRS patients, 11 were severe or critical. Severe and critical HFRS patients were characterized by rodent exposure history, pharyngeal and conjunctival hyperemia, abnormal WBC and PLT counts, and elevated BUN and Cr values. Virus isolation and molecular detection on blood samples from 6 patients showed that three of the six severe patients were positive for hantaan virus (HTNV), and two of the three HTNV positives were also positive for SFTS bunyavirus (SFTSV). The two coinfected patients exhibited different clinical and laboratory characteristics compared to those infected by either virus alone. Coinfection of HTNV and SFTSV leads to severe and complex hemorrhagic fever. Laboratory characteristics, such as the indicators of WBC, PLT, BUN, and Cr, may differ between HFRS and SFTS. These findings have implications and provide references for the diagnosis and treatment of coinfected cases.

The Effects of Bivalirudin and Ordinary Heparin on the Incidence of Bleeding Events and the Level of Inflammation after Interventional Therapy for Acute Myocardial Infarction.

Objective: To evaluate and compare the efficacy, bleeding events, and inflammation levels of optimized bivalirudin versus ordinary heparin in the context of percutaneous coronary intervention (PCI) for patients with acute myocardial infarction. This approach will underscore the comprehensive scope of the study, addressing multiple dimensions of clinical outcomes. Methods: This study involved 120 acute myocardial infarction patients treated from January 2022 to January 2023, randomly allocated into two groups: the control group received ordinary heparin, and the observation group received bivalirudin. Both groups underwent percutaneous coronary intervention (PCI). The study specifically measured coagulation indexes such as prothrombin time (PT) and activated partial thromboplastin time (aPTT), and inflammatory markers including C-reactive protein (CRP) and interleukin-6 (IL-6). Additionally, the incidence of bleeding events and major adverse cardiovascular events (MACE) within 30 days post-PCI were recorded, with bleeding events categorized according to the Bleeding Academic Research Consortium (BARC) criteria and MACE defined by the occurrence of death, non-fatal myocardial infarction, or stroke. Results: No significant differences were observed in coagulation indexes and pre-operation inflammation levels between the two groups (P > .05). However, at 7 days post-operation, despite both groups showing reduced inflammation-NLR decreased by 25%, hs-CRP by 30%, and IL-10 increased by 20%-the bivalirudin group exhibited notably lower incidence rates of various bleeding events (mucosal 2% vs 6%, gingival 1% vs 4%, puncture site 3% vs 8%, and hematuria 1% vs 5%) within 30 days post-PCI compared to the heparin group. TIMI blood flow grades 3 (indicating normal flow) were achieved in 85% of the bivalirudin group compared to 70% in the heparin group. The incidence of MACE was comparable between groups with both reporting a 5% occurrence rate (P > .05). Conclusion: The study reveals that while both bivalirudin and ordinary heparin effectively prevent MACE post-acute myocardial infarction intervention, bivalirudin significantly reduces postoperative bleeding events and maintains comparable anti-inflammatory effects. This suggests its preferable use in clinical settings, particularly in patient populations at high risk for bleeding. Future research could further explore the specific patient characteristics that optimize bivalirudin's benefits over heparin, enhancing tailored therapeutic approaches. This could potentially include randomized trials focusing on patients with different baseline bleeding risks.

Rapid Spread of Severe Fever with Thrombocytopenia Syndrome Virus by Parthenogenetic Asian Longhorned Ticks.

Severe fever with thrombocytopenia syndrome virus (SFTSV) is spreading rapidly in Asia. This virus is transmitted by the Asian longhorned tick (Haemaphysalis longicornis), which has parthenogenetically and sexually reproducing populations. Parthenogenetic populations were found in ≥15 provinces in China and strongly correlated with the distribution of severe fever with thrombocytopenia syndrome cases. However, distribution of these cases was poorly correlated with the distribution of populations of bisexual ticks. Phylogeographic analysis suggested that the parthenogenetic population spread much faster than bisexual population because colonization is independent of sexual reproduction. A higher proportion of parthenogenetic ticks was collected from migratory birds captured at an SFTSV-endemic area, implicating the contribution to the long-range movement of these ticks in China. The SFTSV susceptibility of parthenogenetic females was similar to that of bisexual females under laboratory conditions. These results suggest that parthenogenetic Asian longhorned ticks, probably transported by migratory birds, play a major role in the rapid spread of SFTSV.

Ubiquitin-Modified Proteome of SARS-CoV-2-Infected Host Cells Reveals Insights into Virus-Host Interaction and Pathogenesis.

The outbreak of coronavirus disease 2019 (COVID-19), which is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has posed a serious threat to global public health. The mechanism of pathogenesis and the host immune response to SARS-CoV-2 infection are largely unknown. In the present study, we applied a quantitative proteomic technology to identify and quantify the ubiquitination changes that occur in both the virus and the Vero E6 cells during SARS-CoV-2 infection. By applying label-free, quantitative liquid chromatography with tandem mass spectrometry proteomics, 8943 lysine ubiquitination sites on 3086 proteins were identified, of which 138 sites on 104 proteins were quantified as significantly upregulated, while 828 sites on 447 proteins were downregulated at 72 h post-infection. Bioinformatics analysis suggested that SARS-CoV-2 infection might modulate host immune responses through the ubiquitination of important proteins, including USP5, IQGAP1, TRIM28, and Hsp90. Ubiquitination modification was also observed on 11 SAR-CoV-2 proteins, including proteins involved in virus replication and inhibition of the host innate immune response. Our study provides new insights into the interaction between SARS-CoV-2 and the host as well as potential targets for the prevention and treatment of COVID-19.

Disulfiram inhibits inflammation and fibrosis in a rat unilateral ureteral obstruction model by inhibiting gasdermin D cleavage and pyroptosis.

BACKGROUND: As an inhibitor of GSDMD, Disulfiram (DSL) can significantly inhibit cell pyroptosis. Cell pyroptosis plays an important role in renal fibrosis. METHODS: HK-2 cells were induced by Lps and ATP to form a pyroptosis model, and the cells were treated by DSL. CCK-8 detected the cell activity. Immunofluorescence (IF) detected the GSDMD. ELISA detected the expression of inflammatory cytokines. Flow cytometry and Western blot detected cell apoptosis and pyroptosis. Collagen type I kit detected collagen secretion, and western blot detected fibrosis marker protein expression. Then, a rat model of unilateral ureteral obstruction (UUO) was established. HE staining detected the degree of renal tissue injury, and Masson staining detected the degree of fibrosis. What's more, the apoptosis level of tissue cells was detected by TUNEL. And the inflammatory factors in peripheral blood and renal tissue were detected by ELISA. Furthermore, the expression of GSDMD was detected by immunohistochemistry (IHC), and Western blot was used to detect the expression levels of apoptosis and pyroptosis-related proteins in tissues. RESULTS: It was found that DSL can inhibit the cell membrane perforation of GSDMD-N by inhibiting the cleavage of GSDMD, hence, it inhibited the occurrence of inflammation, cell pyroptosis, and the fibrosis of HK-2 cells. But if the cell has already undergone pyroptosis, DSL does not provide significant prevention. In vivo experiment, it further verified that pretreated DSL had inhibited renal fibrosis injury. CONCLUSION: Disulfiram can inhibit inflammation and fibrosis in renal fibrosis rats by inhibiting GSDMD.

microRNA-183 improve myocardial damager via NF-kb pathway: In vitro and in vivo study.

AIM: The aim of this study is to evaluate the effects of microRNA-183 (miRNA-183) in myocardial damager. METHODS: In the cell experiment, the H9C2 cell was divided into three groups: NC group, Model group, and miRNA group. The cell apoptosis and relative proteins' expressions were measured by flow cytometry and Western blot assay. The in vivo study of the rats was divided into three groups: Sham group, Model group, and miRNA group. The pathology, Infarct size, cell apoptosis, and relative protein expressions were evaluated by hematoxylin and eosin staining, nitro blue tetrazolium staining, terminal deoxynucleotidyl transferase dUTP nick-end labeling assay, and immunohistochemistry. RESULTS: Compared with NC groups, the in vitro and in vivo study showed that cell apoptosis rate of miRNA groups was significantly suppressed (P < 0.05). The pathology and infarct size of miRNA group were significantly improved compared with the NC group. Meanwhile, the relative proteins expression (nuclear factor-κB [NF-kb], caspase-3, Bax, and Bcl-2) of miRNA groups were significantly different compared with those of NC groups ( P < 0.05). CONCLUSION: In vitro and in vivo study revealed that miRNA-183 improves myocardial damager through the NF-κb pathway.

Development and application of a simple recombinase polymerase amplification assay for rapid point-of-care detection of feline herpesvirus type 1.

Feline herpesvirus type 1 (FHV-1) is a highly contagious pathogen of domestic cats and other members of the family Felidae. Point-of-care diagnosis of persistent infection in cats is essential for control of its spread. A recombinase polymerase amplification (RPA) assay (RPA-LFD-FHV) combined with a lateral flow dipstrip (LFD) was developed that uses human body heat for incubation. Sensitivity was evaluated by testing a serial dilution of a control plasmid, and specificity was evaluated by testing related viruses. Swab samples from cats with suspected infection were tested by RPA-LFD-FHV, and the results were compared to those obtained by PCR to evaluate its clinical performance. The RPA-FLD-FHV assay was carried out successfully within 20 min, using body heat for incubation. The RPA-FLD-FHV had a detection limit of 103 copies of the FHV-1 gD gene, which was lower than that of PCR, which was 104 copies. The assay could detect templates of FHV-1 but not those of other feline and canine viruses. Viruses in boiled samples could be efficiently detected by the RPA-FLD-FHV. Thirty-one out of the 80 samples were positive by the RPA-FLD-FHV assay, whereas only 27 were positive by PCR. DNA sequencing confirmed that the four samples that were positive by RPA-FLD-FHV but negative by PCR were indeed positive. These results indicate that RPA-FLD-FHV is applicable for clinical use. The RPA-FLD-FHV assay is a simple, rapid, and reliable method for point-of-care diagnosis of FHV-1 infection.

Mechanism of Action and Risk Prediction of Adiponectin in Cardiovascular Diseases.

Being one of the pivotal adipocytokines, adiponectin binds to various receptors and exerts diverse biological functions, encompassing anti-fibrosis, anti-atherosclerosis, anti-ischemia-reperfusion, regulation of inflammation, and modulation of glucose and lipid metabolism. Alterations in adiponectin levels are observed in patients afflicted with diverse cardiovascular diseases. This paper comprehensively reviews the impact of adiponectin on the pathogenesis and progression of cardiovascular diseases, elucidating the underlying cellular and molecular mechanisms along with the associated cell signaling pathways. Furthermore, it deliberates on the diagnostic and predictive efficacy of adiponectin as a protein marker for cardiovascular diseases. Additionally, it outlines methods for manipulating adiponectin levels in vivo. A thorough understanding of these interconnections can potentially inform clinical strategies for the prevention and management of cardiovascular diseases.

Tick-borne Rickettsia, Anaplasma, Theileria, and enzootic nasal tumor virus in ruminant, PET, and poultry animals in Pakistan.

Introduction: Pakistan is an agricultural country; most of its income is based on livestock rearing. The increasing prevalence of tick-borne pathogens among animals may affect the animal production and livelihood of owners, which eventually derange the economy of a country. Methodology: To further comprehend TBPs, 213 ticks were collected from different animals, including ruminants, pets, and poultry. After molecular and phylogenetic analysis identification, ticks were managed into different pools based on their species level (Hyalomma anatolicum = 80, Rhipicephalus microplus = 35, Hyalomma scupense = 23, Rhipicephalus turanicus = 70, and Rhipicephalus sanguineus = 5). Results and discussion: After tick species identification, further molecular PCR amplification was carried out to screen out the pathogens for the presence of Theileria, Rickettsia, Anaplasma, and enzootic nasal tumor virus (ENTV). The following pathogens were detected: 11 (5.16%) for Anaplasma, 1 (0.47%) for Rickettsia, and 9 (4.23%) for Theileria. Nevertheless, other TBPs that had not been reported so far in Pakistan 3 (1.41%), were positive for enzootic nasal tumor virus (ENTV). Besides, phylogenetic analysis of the enzootic nasal tumor virus (ENTV) strain confirmed its resemblance to the Chinese strain, while Anaplasma has comparability with Pakistan and China, Rickettsia with Pakistan, China, and Iran, and Theileria with India, South Africa, United States, Japan, and Spain. Conclusion: This study reveals that there is a considerably wider range of TBPs held in Pakistan that take in various contagious zoonotic pathogens than was previously thought. This information advances TBP epidemiology and will contribute to upgrade future control measure.

Prevalence and genetic diversity of rodent-associated Bartonella in Hulunbuir border regions, China.

Bartonella spp. are globally distributed gram-negative facultative intracellular bacteria that infect a wide range of hosts. Rodents are natural reservoirs of many Bartonella species, some of which are also pathogenic to humans. The rapid development of transportation and tourism has highlighted the risk of Bartonella transmission to humans. Thus, it is essential to maintain surveillance of Bartonella spp. infections in rodents. In China, Bartonella spp. infections have been monitored in various areas; however, these have not included the Hulunbuir border regions. In the present study, we monitored the prevalence and genetics of rodent-associated Bartonella spp. in the Hulunbuir border regions. Eleven rodent species were captured at five ports. Eight species were confirmed as Bartonella-positive using quantitative PCR assay, with an overall positivity rate of 20.05 %. Lasiopodomys brandtii was the predominant rodent species captured for Bartonella detection. Sequencing and phylogenetic analysis (using the maximum likelihood method) revealed the presence of three Bartonella species in these rodents, including two pathogenic to humans, namely, Bartonella alsatica and Bartonella grahamii. B. grahamii was the predominant Bartonella species identified in the rodents. Taken together, these results highlight the prevalence and genetic diversity of Bartonella spp. in rodents in the Hulunbuir border regions, indicating the need for risk assessment of human spillover.

Disruption of bacterial biofilms by a green synthesized artemisinin nano-copper nanomaterial.

Bacterial biofilms are associated with antibiotic resistance and account for ∼80% of all bacterial infections. In this study, we explored novel nanomaterials for combating bacteria and their biofilms. Artemisinin nano-copper (ANC) was synthesized using a green synthesis strategy, and its shape, size, structure, elemental composition, chemical valence, zeta potential, and conductivity were characterized using transmission electron microscopy, X-ray diffractometer, X-ray photoelectron spectroscopy, zeta potential, and dynamic light scattering. The results showed that ANC was successfully synthesized utilizing a liquid phase chemical reduction method using chitosan as a modified protectant and l-ascorbic acid as a green reducing agent. The stability of ANC was evaluated using dynamic light scattering. The results showed that the particle size of ANC at different concentrations was comparable to that of the original solution after 7 days of storage, and there was no significant change in the polydispersity index (P > 0.05). The antibacterial effects of ANC on Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) were determined by disc diffusion and broth dilution methods. The results demonstrated that ANC inhibited and killed E. coli and S. aureus. The effect of ANC on bacterial biofilms was investigated using crystal violet staining, scanning electron microscopy, laser confocal microscopy, and quantitative polymerase chain reaction. The results showed that ANC treatment was able to destroy bacterial biofilms and downregulate biofilm- and virulence-related genes in E. coli (HlyA, gyrA, and F17) and S. aureus (cna, PVL, ClfA, and femB). Green-synthesized ANC possesses excellent antibiofilm properties and is expected to exhibit antibacterial and antibiofilm properties.

A modified recombinant adenovirus vector containing dual rabies virus G expression cassettes confers robust and long-lasting humoral immunity in mice, cats, and dogs.

During the COVID-19 epidemic, the incidence of rabies has increased in several countries, especially in remote and disadvantaged areas, due to inadequate surveillance and declining immunization coverage. Multiple vaccinations with inactivated rabies virus vaccines for pre- or post-exposure prophylaxis are considered inefficient, expensive and impractical in developing countries. Herein, three modified human recombinant adenoviruses type 5 designated Adv-RVG, Adv-E1-RVG, and Adv-RVDG, carrying rabies virus G (RVG) expression cassettes in various combinations within E1 or E3 genomic regions, were constructed to serve as rabies vaccine candidates. Adv-RVDG mediated greater RVG expression both in vitro and in vivo and induced a more robust and durable humoral immune response than the rabies vaccine strain SAD-L16, Adv-RVG, and Adv-E1-RVG by more effectively activating the dendritic cells (DCs) - follicular helper T (Tfh) cells - germinal centre (GC) / memory B cells (MBCs) - long-lived plasma cells (LLPCs) axis with 100% survival after a lethal RABV challenge in mice during the 24-week study period. Similarly, dogs and cats immunized with Adv-RVDG showed stronger and longer-lasting antibody responses than those vaccinated with a commercial inactivated rabies vaccine and showed good tolerance to Adv-RVDG. In conclusion, our study demonstrated that simultaneous insertion of protective antigens into the E1 and E3 genomic regions of adenovirus vector can significantly enhance the immunogenicity of adenoviral-vectored vaccines, providing a theoretical and practical basis for the subsequent development of multivalent and multi-conjugated vaccines using recombinant adenovirus platform. Meanwhile, our data suggest Adv-RVDG is a safe, efficient, and economical vaccine for mass-coverage immunization.

Amugulang virus, a novel hantavirus harboured by small rodents in Hulunbuir, China.

The Hulunbuir region, known for its diverse terrain and rich wildlife, is a hotspot for various natural epidemic diseases. Between 2021 and 2023, we collected 885 wild rodent samples from this area, representing three families, seven genera, and eleven species. Metagenomic analysis identified three complete nucleic acid sequences from the S, M, and L segments of the Hantaviridae family, which were closely related to the Khabarovsk virus. The nucleotide coding sequences for S, M, and L (1392 nt, 3465 nt, and 6491 nt, respectively) exhibited similarities of 82.34%, 81.68%, and 81.94% to known sequences, respectively, while protein-level analysis indicated higher similarities of 94.92%, 94.41%, and 95.87%, respectively. Phylogenetic analysis placed these sequences within the same clade as the Khabarovsk, Puumala, Muju, Hokkaido, Topografov, and Tatenalense viruses, all of which are known to cause febrile diseases in humans. Immunofluorescence detection of nucleic acid-positive rodent kidney samples using sera from patients with hemorrhagic fever and renal syndrome confirmed the presence of viral particles. Based on these findings, we propose that this virus represents a new member of the Hantaviridae family, tentatively named the Amugulang virus, after its primary distribution area.

Analysis of the diversity of tick-borne viruses at the border areas in Liaoning Province, China.

Ticks play a significant role in transmitting arboviruses, which pose a risk to human and animal health. The region of Liaoning Province, China, with abundant plant resources with multiple tick populations, has reported several tick-borne diseases. However, there remains a scarcity of research on the composition and evolution of the tick virome. In this study, we conducted the metagenomic analysis of 561 ticks in the border area of Liaoning Province in China and identified viruses related to known diseases in humans and animals, including severe fever with thrombocytopenia syndrome virus (SFTSV) and nairobi sheep disease virus (NSDV). Moreover, the groups of tick viruses were also closely related to the families of Flaviviridae, Parvoviridae, Phenuiviridae, and Rhabdoviridae. Notably, the Dabieshan tick virus (DBTV) of the family Phenuiviridae was prevalent in these ticks, with the minimum infection rate (MIR) of 9.09%, higher than previously reported in numerous provinces in China. In addition, sequences of tick-borne viruses of the family Rhabdoviridae have first been reported from the border area of Liaoning Province, China, after being described from Hubei Province, China. This research furthered the insight into pathogens carried by ticks in the northeastern border areas of China, offering epidemiological information for possible forthcoming outbreaks of infectious diseases. Meanwhile, we provided an essential reference for assessing the risk of tick bite infection in humans and animals, as well as for exploring into the evolution of the virus and the mechanisms of species transmission.

Metavirome of 31 tick species provides a compendium of 1,801 RNA virus genomes.

The increasing prevalence and expanding distribution of tick-borne viruses globally have raised health concerns, but the full repertoire of the tick virome has not been assessed. We sequenced the meta-transcriptomes of 31 different tick species in the Ixodidae and Argasidae families from across mainland China, and identified 724 RNA viruses with distinctive virome compositions among genera. A total of 1,801 assembled and complete or nearly complete viral genomes revealed an extensive diversity of genome architectures of tick-associated viruses, highlighting ticks as a reservoir of RNA viruses. We examined the phylogenies of different virus families to investigate virome evolution and found that the most diverse tick-associated viruses are positive-strand RNA virus families that demonstrate more ancient divergence than other arboviruses. Tick-specific viruses are often associated with only a few tick species, whereas virus clades that can infect vertebrates are found in a wider range of tick species. We hypothesize that tick viruses can exhibit both 'specialist' and 'generalist' evolutionary trends. We hope that our virome dataset will enable much-needed research on vertebrate-pathogenic tick-associated viruses.

Excitatory effect of histamine on rat spinal motoneurons by activation of both H1 and H2 receptors in vitro.

The central histaminergic nervous system, originating from the tuberomammillary nucleus of the hypothalamus, widely innervates almost the whole brain as well as the spinal cord. However, the effect of histamine on spinal motoneurons, the final common path for motor control, is still unknown. By using 8-14-day-old rat spinal slice preparations and intracellular recordings, the effect of histamine on motoneurons in lumbar spinal cord and the underlying mechanisms were studied. Bath application of histamine (30-300 µM) induced a membrane depolarization in the majority of recorded spinal motoneurons (78/90, 86%). Perfusing slices with tetrodotoxin or low-Ca(2+) /high-Mg(2+) medium did not block the histamine-induced excitation, indicating a direct postsynaptic action of histamine on motoneurons. Separate application of the selective histamine H(1) receptor antagonist mepyramine or the selective histamine H(2) receptor antagonist ranitidine partially suppressed the histamine-induced excitation, whereas a combination of ranitidine and mepyramine totally blocked the excitatory effect of histamine on motoneurons. On the other hand, both the selective histamine H(1) receptor agonist 2-pyridylethylamine and the selective histamine H(2) receptor agonist dimaprit mimicked the excitation of histamine on spinal motoneurons. These agonist-induced excitations were also blocked by mepyramine or ranitidine. Furthermore, histamine affected membrane input resistance and potentiated repetitive firing behavior of spinal motoneurons. These results demonstrate that histamine excites rat spinal motoneurons via the histamine H(1) and H(2) receptors and increases their excitability, suggesting that the hypothalamospinal histaminergic fibers may directly modulate final motor outputs and actively regulate ongoing motor execution andspinal motor reflexes.

A Phi29-based unbiased exponential amplification and genotyping approach improves pathogen detection in tick samples.

Ticks are vectors for many infectious diseases, such as spotted fever group (SFG) rickettsioses and borreliosis, and are valuable in the study of pathogen ecology. Ticks have several growth stages that vary considerably in size; therefore, in most cases, DNA extracted from ticks is insufficient for subsequent studies, particularly for multiple pathogen screening and genotyping. Unbiased amplification of DNA from tick samples before analysis is a major requirement for subsequent ecological surveys and other studies. Phi29 DNA polymerase, an enzyme that exhibits strand displacement activity, can exponentially amplify DNA randomly, generating large quantities of DNA. In the present study, we developed a Phi29-based unbiased exponential amplification (PEA) assay to obtain sufficient tick DNA for genetic analysis. By using tick-borne pathogen detection and genotyping as a model, we tested and evaluated the feasibility of the assay. DNA was extracted from single ticks and subjected to PEA. The results showed that tick DNA could be amplified up to 105 fold. The amplified products were successfully used for pathogen screening and genotyping. Rickettsia was successfully detected and genotyped in samples with amplified DNA from single ticks. Furthermore, we identified a new genotype of Rickettsia from ticks collected from Dandong city, Liaoning province, Northeast China. This PEA assay is universal and can be extended to other applications where the quantity of DNA is greatly limited.

Identification of severe fever with thrombocytopenia syndrome virus genotypes in patients and ticks in Liaoning Province, China.

BACKGROUND: Severe fever with thrombocytopenia syndrome (SFTS), caused by the SFTS virus (SFTSV), is an acute infectious disease transmitted by ticks that has recently been identified. There are no reports of epidemic serotypes in Liaoning Province, PR China. The aim of this study was, therefore, to identify genotypes of SFTSV in this province. METHODS: In 2019, quantitative PCR testing was performed on 17 patients suspected of being infected with SFTS in Liaoning Province and on 492 ticks from the counties and cities surrounding the patients' residences. Four samples were subjected to virus isolation and whole-genome amplification. RESULTS: Molecular diagnostic results confirmed SFTSV infection in five of the 17 suspected cases of SFTS and in 12 of the 492 ticks, with a prevalence of 2.4%. Four strains of SFTSV were successfully isolated from patients' blood and ticks. Phylogenetic analysis after whole-genome amplification and sequencing showed that they all belonged to genotype A of SFTSV. CONCLUSIONS: This study is the first to determine the genotype of SFTSV in patients and ticks in Liaoning Province, PR China. The results deepen our understanding of the SFTS epidemic and provide information on the variability in mortality rate among genotypes.