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.

Skin infectome of patients with a tick bite history.

Introduction: Ticks are the most important obligate blood-feeding vectors of human pathogens. With the advance of high-throughput sequencing, more and more bacterial community and virome in tick has been reported, which seems to pose a great threat to people. Methods: A total of 14 skin specimens collected from tick-bite patients with mild to severe symptoms were analyzed through meta-transcriptomic sequencings. Results: Four bacteria genera were both detected in the skins and ticks, including Pseudomonas, Acinetobacter, Corynebacterium and Propionibacterium, and three tick-associated viruses, Jingmen tick virus (JMTV), Bole tick virus 4 (BLTV4) and Deer tick mononegavirales-like virus (DTMV) were identified in the skin samples. Except of known pathogens such as pathogenic rickettsia, Coxiella burnetii and JMTV, we suggest Roseomonas cervicalis and BLTV4 as potential new agents amplified in the skins and then disseminated into the blood. As early as 1 day after a tick-bite, these pathogens can transmit to skins and at most four ones can co-infect in skins. Discussion: Advances in sequencing technologies have revealed that the diversity of tick microbiome and virome goes far beyond our previous understanding. This report not only identifies three new potential pathogens in humans but also shows that the skin barrier is vital in preventing horizontal transmissions of tick-associated bacteria or virus communities to the host. It is the first research on patients' skin infectome after a tick bite and demonstrates that more attention should be paid to the cutaneous response to prevent tick-borne illness.

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.

Dermacentor silvarum, a Medically Important Tick, May Not Be a Competent Vector to Transmit Jingmen Tick Virus.

Background: Jingmen tick virus (JMTV) has attracted great attention due to its potential pathogenicity in humans and its transmission by ticks. Dermacentor silvarum (D. silvarum) is one of the dominant tick species in northeastern China, and can transmit many pathogens to humans and animals. However, there have been no report of transmission of JMTV by D. silvarum. Materials and Methods: Ticks were collected from vegetation at the Aershan Port in Inner Mongolia in April 2019. And we do attempt to infect D. silvarum with JMTV by the immersion technique in laboratory conditions. The transmission of JMTV was examined by reverse transcriptase PCR, fluorescence in situ hybridization, and indirect immunofluorescence assay. Statistical analysis was performed using SPSS 24.0. Results: We found that JMTV may only be maintained in the tick without replication, and could not be transmitted to a host following transstadial transmission. Moreover, no virus colonization was found in the midgut or salivary glands of unfed D. silvarum; therefore, D. silvarum may not be susceptible to JMTV infection and therefore unlikely to carry and transmit JMTV. Conclusion: Our study has to some extent filled the knowledge gap regarding the possibility of JMTV transmission by a medically important tick vector, D. silvarum.

Chronic Progression of Lung Cancer Recurrence After Surgery: Warning Role of Postoperative Pneumonia.

PURPOSE: The association between the process of postoperative pneumonia and lung cancer recurrence remains elusive in lung cancer surgery. Herein, the association between postoperative pneumonia and lung cancer recurrence was investigated, emphasizing the warning role of postoperative specific pneumonia in primary lung cancer resection patients. METHODS: The occurrence of postoperative pneumonia was assessed in 4-6 months (PPFS), 7-12 months (PPST), and lung cancer recurrence within 1 year (LRO) in 332 patients. The primary outcome was the development of PPST and LRO according to PPFS occurrence. The relevant risk factors of PPFS, PPST, and LRO were identified through multivariable regression analysis. RESULTS: During follow-up, 151 (45.48%) participants experienced PPFS. Irrespective of the existing postoperative pneumonia in 1-3 months (PPOT), PPFS significantly increased the risk of PPST (P < 0.01) and LRO (P < 0.01), and persistent PPST further increased the risk of LRO (P < 0.001). The generalized estimating equation identified chemotherapy as an independent risk factor for PPFS and PPST. CONCLUSION: PPFS was associated with the increased risk of PPST and LRO. Postoperative pulmonary inflammation assessed 4 months post-surgery also significantly influenced LRO development, indicating a need for close follow-up of lung inflammatory conditions to improve patient outcomes.

The complete mitochondrial genome of Amblyomma geoemydae (Ixodida: Ixodidae).

The complete mitochondrial genome of Amblyomma geoemydae is reported for the first time in this study. Its entire mitogenome is 14,780 bp in length, contained 13 protein-coding genes, two ribosomal RNA genes, 22 transfer RNA genes, and two non-coding regions. The phylogenetic analysis by Maximum-likelihood method show that A. geoemydae and the others of genus Amblyomma are in the same clade, indicating that A. geoemydae belongs to the genus Amblyomma.

Rapid Detection of Ustilaginoidea virens from Rice using Loop-Mediated Isothermal Amplification Assay.

Ustilaginoidea virens is an important fungus that causes rice false smut disease. This disease significantly reduces both grain yield and quality. Various methods have been developed for the detection of U. virens but most of these methods need sophisticated equipment such as a thermal cycler. Here, we present a loop-mediated isothermal amplification (LAMP) assay for the specific detection of U. virens. This assay used a specific region of the UvG-ß1 gene (212-bp region) to design six LAMP primers. The LAMP assay was optimized by the combination of rapidity, simplicity, and high sensitivity for the detection of about 1 pg of target genomic DNA in the reaction whereas, with polymerase chain reaction (PCR), there was no amplification of DNA with concentrations less than 1 ng. Among the genomic DNA of 22 fungus species and two strains of U. virens, only the tube containing the DNA of U. virens changed to yellowish green with SYBR Green I. The color change was indicative of DNA amplification. No DNA was amplified from either the other 22 fungus species or the negative control. Moreover, 20 spikelets and 22 rice seed samples were used for the detection of rice false smut via LAMP. The results were comparable with conventional PCR. We conclude that gene UvG-ß1 coupled with LAMP assay, can be used for the detection and identification of U. virens gene via LAMP.

[Primary cultured neonate rat sinus node cells: morphology and expression of kir2.1 protein].

OBJECTIVE: To investigate the expression of kir2.1 protein in primary cultured sinus node cells and establish a reliable technique to locate, culture and characterize neonatal rat sinus node cells. METHODS: In paraffin sections, the location and morphology of the neonatal rat sinus node cells were observed by HE staining, silver nitrate staining, myelin staining and phosphotungstic acid-hematoxylin (PTAH) staining. Primary cell culture from the neonatal rat sinus node was conducted to observe the spontaneous contraction frequency, cell morphology and kir2.1 protein expression. RESULTS: Combination of the 3 staining methods allowed accurate localization of the sino-atrial nodal (SAN) tissue, and among the cultured cells in the SAN, at least 3 distinct types of cells with spontaneous contraction were observed. The majority of the contracting cells were spindle cells and their construction and impulse frequency indicated their identity as pacemaker cells, while the triangular and irregular cells resembled the atrial muscle cells. A lower expression level of kir2.1 protein was detected in SAN cells than in the atrial and ventricular myocytes of the neonatal rats. CONCLUSION: Combination of silver nitrate staining, myelin staining and PTAH staining identifies the exact location of the sinus node tissue, and cultured sinus node cells have lower expression of kir2.1 protein than the atrial and ventricular myocytes of neonatal rats.