Isolation of Clostridium perfringens type A from wild bharals (Pseudois nayaur) following sudden death in Tibet, China.

Dozens of wild bharals died suddenly in Tibet. Necropsy showed severe congestion and hemorrhage in multiple organs, with large numbers of Gram-positive bacilli. Strains of Clostridium perfringens type A were isolated from the different organs and the intestinal contents. The other possible pathogens were ruled out by PCR.

Antiviral C-geranylated flavonoids from Artocarpus communis.

Ten C-geranylated flavonoids, along with three known analogues, were isolated from the leaves of Artocarpus communis. The chemical structures of these compounds were unambiguously determined via comprehensive spectroscopic analysis, single-crystal X-ray diffraction experiments, and quantum chemical electronic circular dichroism calculations. Structurally, artocarones A-I (1-9) represent a group of unusual, highly modified C-geranylated flavonoids, in which the geranyl chain is cyclised with the ortho-hydroxy group of flavonoids to form various heterocyclic scaffolds. Notably, artocarones E and G-I (5 and 7-9) feature a 6H-benzo[c]chromene core that is hitherto undescribed in C-geranylated flavonoids. Artocarone J (10) is the first example of C-9-C-16 connected C-geranylated aurone. Meanwhile, the plausible biosynthetic pathways for these rare C-geranylated flavonoids were also proposed. Notably, compounds 1, 2, 4, 8, 11, and 12 exhibited promising in vitro inhibitory activities against respiratory syncytial virus and herpes simplex virus type 1.

Virological characteristics of SARS-CoV-2 Omicron BA.5.2.48.

With the prevalence of sequentially-emerged sublineages including BA.1, BA.2 and BA.5, SARS-CoV-2 Omicron infection has transformed into a regional epidemic disease. As a sublineage of BA.5, the BA.5.2.48 outbroke and evolved into multi-subvariants in China without clearly established virological characteristics. Here, we evaluated the virological characteristics of two isolates of the prevalent BA.5.2.48 subvariant, DY.2 and DY.1.1 (a subvariant of DY.1). Compared to the normal BA.5 spike, the double-mutated DY.1.1 spike demonstrates efficient cleavage, reduced fusogenicity and higher hACE2 binding affinity. BA.5.2.48 demonstrated enhanced airborne transmission capacity than BA.2 in hamsters. The pathogenicity of BA.5.2.48 is greater than BA.2, as revealed in Omicron-lethal H11-K18-hACE2 rodents. In both naïve and convalescent hamsters, DY.1.1 shows stronger fitness than DY.2 in hamster turbinates. Thus regional outbreaking of BA.5.2.48 promotes the multidirectional evolution of its subvariants, gaining either enhanced pathogenicity or a fitness in upper airways which is associated with higher transmission.

Schisandra chinensis (Turcz.) Baill. polysaccharide inhibits influenza A virus in vitro and in vivo.

Influenza virus is prone to seasonal spread and widespread outbreaks, which pose important challenges to public health security. Therefore, it is important to effectively prevent and treat influenza virus infection. Schisandra polysaccharide (SPJ) is a polysaccharide derived from the fruit of Schisandra chinensis (Turcz.) Baill. In this study, we evaluated the antiviral activity of SPJ in vitro and in vivo, especially against influenza A virus (IAV) infection. By analyzing SPJ structure and monosaccharide composition, the molecular weight of SPJ was determined to be 115.5 KD, and it is composed of galacturonic acid (89.4%), rhamnose (0.8%), galactose (4.4%), arabinose (3.8%), and glucose (1.7%). Immunofluorescence analysis showed that SPJ treatment reduced the positive rate of viral nucleoproteins in cells, indicating that the compound had an inhibitory effect on influenza virus replication. Furthermore, SPJ therapy improved the survival of infected mice. Lung virus titer assays indicated that SPJ treatment significantly reduced viral loading in the lung tissue of infected mice and alleviated the pathological damage caused by influenza virus infection. Moreover, SPJ reduced cytokine expression during influenza virus challenge. In conclusion, SPJ has anti-influenza virus effects and may have potential as an anti-influenza drug candidate in further clinical studies.

Proteomic and Metabolomic Characterization of SARS-CoV-2-Infected Cynomolgus Macaque at Early Stage.

Although tremendous effort has been exerted to elucidate the pathogenesis of severe COVID-19 cases, the detailed mechanism of moderate cases, which accounts for 90% of all patients, remains unclear yet, partly limited by lacking the biopsy tissues. Here, we established the COVID-19 infection model in cynomolgus macaques (CMs), monitored the clinical and pathological features, and analyzed underlying pathogenic mechanisms at early infection stage by performing proteomic and metabolomic profiling of lung tissues and sera samples from COVID-19 CMs models. Our data demonstrated that innate immune response, neutrophile and platelet activation were mainly dysregulated in COVID-19 CMs. The symptom of neutrophilia, lymphopenia and massive "cytokines storm", main features of severe COVID-19 patients, were greatly weakened in most of the challenged CMs, which are more semblable as moderate patients. Thus, COVID-19 model in CMs is rational to understand the pathogenesis of moderate COVID-19 and may be a candidate model to assess the safety and efficacy of therapeutics and vaccines against SARS-CoV-2 infection.

Characterization of Canine Influenza Virus A (H3N2) Circulating in Dogs in China from 2016 to 2018.

Avian H3N2 influenza virus follows cross-host transmission and has spread among dogs in Asia since 2005. After 2015-2016, a new H3N2 subtype canine influenza epidemic occurred in dogs in North America and Asia. The disease prevalence was assessed by virological and serological surveillance in dogs in China. Herein, five H3N2 canine influenza virus (CIV) strains were isolated from 1185 Chinese canine respiratory disease samples in 2017-2018; these strains were on the evolutionary branch of the North American CIVs after 2016 and genetically far from the classical canine H3N2 strain discovered in China before 2016. Serological surveillance showed an HI antibody positive rate of 6.68%. H3N2 was prevalent in the coastal areas and northeastern regions of China. In 2018, it became the primary epidemic strain in the country. The QK01 strain of H3N2 showed high efficiency in transmission among dogs through respiratory droplets. Nevertheless, the virus only replicated in the upper respiratory tract and exhibited low pathogenicity in mice. Furthermore, highly efficient transmission by direct contact other than respiratory droplet transmission was found in a guinea pig model. The low-level replication in avian species other than ducks could not facilitate contact and airborne transmission in chickens. The current results indicated that a novel H3N2 virus has become a predominant epidemic strain in dogs in China since 2016 and acquired highly efficient transmissibility but could not be replicated in avian species. Thus, further monitoring is required for designing optimal immunoprophylactic tools for dogs and estimating the zoonotic risk of CIV in China.

Transcriptome sequencing and endogenous phytohormone analysis reveal new insights in CPPU controlling fruit development in kiwifruit (Actinidia chinensis).

Kiwifruit (Actinidia chinensis) is a rich nutritious fruit crop owing to a markedly higher content of vitamin C and minerals. To promote fruit set and to increase the yield of kiwifruit, forchlorfenuron (CPPU) has been widely applied. However, the molecular details regarding CPPU controlling kiwifruit development, especially at the fastest fruit growth stage, remain unknown. In the present study, we measured the effect of CPPU on developmental regulation in red-fleshed kiwifruit (Actinidia chinensis 'Hongyang'). Additionally, a cytological analysis was performed to clarify the precise changes in the cell structure of the CPPU-treated kiwifruits. Moreover, the concentration of endogenous phytohormones, including indoleacetic acid (IAA), zeatin (ZT), gibberellic acid 3 (GA3), and abscisic acid (ABA), were measured by Enzyme-linked Immunosorbent Assay (ELISA). Furthermore, RNA-Seq was performed to dissect the complicated molecular mechanisms, with a focus on biosynthesis, metabolism, and signaling compounds, such as endogenous hormones, sugars, and L-ascorbic acid. Our results demonstrated that CPPU treatment not only regulates the size and weight of a single fruit but also improves the quality in 'Hongyang' kiwifruit through the accumulation of both soluble sugar and vitamin C. It was also seen that CPPU regulates kiwifruit development by enhancing cell expansion of epidermal cells and parenchyma cells, while, promoting cell division of subepidermal cells. Additionally, CPPU significantly increased the gibberellin and cytokinin biosynthetic pathway and signaling, while repressing auxin and ABA biosynthetic pathway; thus, signaling plays an essential role in CPPU controlling kiwifruit development. Notably, transcriptomic analysis revealed that a total of 2244 genes, including 352 unannotated genes, were differentially expressed in kiwifruits because of CPPU treatment, including 127 transcription factors. These genes are mainly enriched in plant hormone signal transduction, photosynthesis, MAPK signaling pathway, starch and sucrose metabolism, and phenylpropanoid biosynthesis. Overall, our results highlight that CPPU regulation of kiwifruit development is mainly associated with an antagonistic and/or synergistic regulatory role of endogenous phytohormones, and enhancing the energy supply. This provides new insights into the molecular details of CPPU controlling kiwifruit development at the fastest fruit growth stage, which is of agricultural importance for kiwifruit breeding and crop improvement.

Determination of delay time in individual transfer function for central aortic pressure reconstruction.

In previous research, time-delay (Δt) was a more important parameter than the reflection coefficient in the individual transfer function of central aortic pressure reconstruction. The Δt can be obtained by electrocardiography (ECG) or phonocardiography (PCG). Because the pre-ejection period remains an uncertain factor, the present study used ECG and PCG to define the delay time and analyzed the accuracy of the reconstruction results. The Δt pre is the actual delay time derived from the aorta to the carotid pressure wave, Δt PCG is the time delay between the aortic valve component of the second heart sound and the dicrotic incisura of the carotid pressure wave, and Δt ECG represents the delay from the interval of the ECG R-peak to the foot of the carotid pressure wave. Compared with the measured aortic pressure, the reconstruction result obtained by Δt=Δt PCG slightly differed from the best result estimated by Δt=Δt pre. However, the differences between the result obtained by Δt=Δt ECG and the best result were significant in terms of the diastolic blood pressure, and pulse pressure, and especially in terms of the augmentation index and root-mean-square-error. Thus, the Δt should be determined by PCG for central aortic pressure reconstruction in practice.