Silica Nanoparticle Size Determines the Mechanisms Underlying the Inhibition of Iron Oxide Nanoparticle Uptake by Daphnia magna.

Aquatic environments are complicated systems that contain different types of nanoparticles (NPs). Nevertheless, recent studies of NP toxicity, and especially those that have focused on bioaccumulation have mostly investigated only a single type of NPs. Assessments of the environmental risks of NPs that do not consider co-exposure regimes may lead to inaccurate conclusions and ineffective environmental regulation. Thus, the present study examined the effects of differently sized silica NPs (SiO2 NPs) on the uptake of iron oxide NPs (Fe2O3 NPs) by the zooplankton Daphnia magna. Both SiO2 NPs and Fe2O3 NPs were well dispersed in the experimental medium without significant heteroaggregation. Although all three sizes of SiO2 NPs inhibited the uptake of Fe2O3 NPs, the underlying mechanisms differed. SiO2 NPs smaller than the average mesh size (∼200 nm) of the filtering apparatus of D. magna reduced the accumulation of Fe2O3 NPs through uptake competition, whereas larger SiO2 NPs inhibited the uptake of Fe2O3 NPs mainly by reducing the water filtration rate of the daphnids. Overall, in evaluations of the risks of NPs in the natural environment, the different mechanisms underlying the effects of NPs of different sizes on the uptake of dissimilar NPs should be considered.

Immunogenicity and safety of a new hexavalent rotavirus vaccine in Chinese infants: A randomized, double-blind, placebo-controlled phase 2 clinical trial.

Rotavirus remains a major cause of diarrhea among 5-y-old children, and vaccination is currently the most effective and economical measure. We conducted a randomized, double-blind, placebo-controlled phase II clinical trial designed to determine the dosage, immunogenicity, and safety profile of a novel hexavalent rotavirus vaccine. In total, 480 eligible healthy infants, who were 6-12 weeks of age at the time of randomization were randomly allocated (1:1:1) to receive 105.5 focus-forming unit (FFU) or 106.5FFU of vaccine or placebo on a 0, 28 and 56-d schedule. Blood samples were collected 28 d after the third dose to assess rotavirus immunoglobulin A (IgA) antibody levels. Adverse events (AEs) up to 28 d after each dose and serious adverse events (SAEs) up to 6 months after the third dose were recorded as safety measurements. The anti-rotavirus IgA seroconversion rate of the vaccine groups reached more than 70.00%, ranging from 74.63% to 76.87%. The postdose 3 (PD3) geometric mean concentrations (GMCs) of anti-rotavirus IgA among vaccine recipients ranged from 76.97 U/ml to 84.46 U/ml. At least one solicited AE was recorded in 114 infants (71.25%) in the high-dose vaccine group, 106 infants (66.25%) in the low-dose vaccine group and 104 infants (65.00%) in the placebo group. The most frequently solicited AE was fever. The novel oral hexavalent rotavirus vaccine was safe and immunogenic in infants support the conclusion to advance the candidate vaccine for phase 3 efficacy trials.

[Effects of electroacupuncture on gait and proliferation and differentiation of muscle satellite cell in rats with acute blunt trauma of gastrocnemius muscle].

OBJECTIVE: To observe the effects of electroacupuncture on threshold of pain, gait, proliferation and differentiation of muscle satellite cell in rats with acute blunt trauma of gastrocnemius muscle, and to explore the possible mechanism of electroacupuncture in promoting the repair of acute injury of skeletal muscle. METHODS: A total of 48 SD rats were randomly divided into a blank group (6 rats), a model group (24 rats) and an electroacupuncture group (18 rats). In the model group and the electroacupuncture group, the model of acute blunt trauma of gastrocnemius muscle was established by self-made impactor. In the electroacupuncture group, electroacupuncture was applied at "Chengshan" (BL 57) and "Yanglingquan" (GB 34) on the right side, with disperse-dense wave, in frequency of 2 Hz/100 Hz, once a day, 30 min each time. Electroacupuncture intervention was performed for 3, 7 and 14 days according to the sampling time. On the 1st, 3rd, 7th and 14th days after modeling, the mechanical withdrawal pain threshold of hindfoot was detected by Von Frey method; the standing time and the maximum contact area of the right hindfoot were recorded by Cat Walk XTTM animal gait analysis instrument; the morphology of the right gastrocnemius muscle and the number of inflammatory cells were observed by HE staining; the positive expression of paired box gene 7 (Pax7) and myogenic differentiation (MyoD) of the right gastrocnemius muscle was detected by immunofluorescence. RESULTS: After modeling, the muscle fiber rupture and massive infiltration of red blood cells and inflammatory cells were observed in the right gastrocnemius muscle; after electroacupuncture intervention, the morphology of muscle fiber was intact and the infiltration of inflammatory cells was improved. Compared with the blank group, in the model group, the differences of mechanical withdrawal pain threshold between the left and right foot were increased (P<0.05), the standing time was shortened and the maximum contact area of the right hindfoot was decreased (P<0.05), the number of inflammatory cells and the positive expression of Pax7 and MyoD of the right gastrocnemius muscle were increased (P<0.05) on the 1st, 3rd, 7th and 14th days after modeling. Compared with the model group, in the electroacupuncture group, the differences of mechanical withdrawal pain threshold were decreased (P<0.05), the standing time was prolonged (P<0.05), the number of inflammatory cells of right gastrocnemius muscle was decreased (P<0.05) on the 7th and 14th days after modeling; the maximum contact area of the right hindfoot was increased (P<0.05), the positive expression of MyoD of the right gastrocnemius muscle was increased (P<0.05) on the 3rd, 7th and 14th days after modeling; the positive expression of Pax7 of the right gastrocnemius muscle was increased (P<0.05) on the 3rd day after modeling. CONCLUSION: Electroacupuncture can effectively improve the pain threshold and gait in rats with acute blunt trauma of gastrocnemius muscle, and promote the repair of skeletal muscle injury, the mechanism may be related to the up-regulation of Pax7 and MyoD, so as to promoting the proliferation and differentiation of muscle satellite cell.

Accumulation of nanoplastics in human cells as visualized and quantified by hyperspectral imaging with enhanced dark-field microscopy.

Nanoplastic (NP) pollution is receiving increasing attention regarding its potential effects on human health. The identification and quantification of intracellular NPs are prerequisites for an accurate risk assessment, but appropriate methods are lacking. Here we present a label-free technique to simultaneously visualize and quantify the bioaccumulation of NPs based on hyperspectral imaging with enhanced dark-field microscopy (HSI-DFM). Using polystyrene NPs (PS NPs) as representative particles, the construction of a hyperspectral library was optimized first with more accurate NP identification achieved when the library was based on intracellular instead of extracellular PS NPs. The PS NPs used herein were labeled with a green fluorescent dye so that the accuracy of HSI-DFM in identifying and quantifying intracellular NPs can be evaluated, by comparing the results with those obtained by fluorescence microscopy and flow cytometry. The validation of HSI-DFM for use in determinations of the NP concentration at the single-cell level allows analyses of the accumulation kinetics of NPs in single living cells. The utility of HSI-DFM in different cell lines and with NPs differing in their chemical composition was also demonstrated. HSI-DFM therefore provides a new approach to studies of the accumulation and distribution of NPs in human cells.

Preoperative computed tomography-guided transscapular sens-cure needle localization for pulmonary nodule located behind the scapula.

BACKGROUND: Video-assisted thoracoscopic surgery (VATS) is an approach that is commonly used to resect pulmonary nodules (PNs). However, when these PNs are located behind the scapula, a transscapular access approach is generally required. In this study, the safety, efficacy, and feasibility of preoperative computed tomography (CT)-guided Sens-cure needle (SCN) localization was assessed for PNs located behind the scapula. METHODS: From January 2020 - June 2022, a total of 122 PN patients in our hospital underwent preoperative CT-guided SCN localization and subsequent VATS resection, of whom 12 (9.8%) exhibited PNs behind the scapula necessitating a transscapular approach for this localization procedure. RESULTS: This study included 12 patients, each of whom had one PN located behind the scapula. The CT-guided transscapular SCN localization approach was successful in all patients, and no complications near the operative site were observed. The median localization time was 12 min, and 2 (16.7%) and 1 (8.3%) patients respectively developed pneumothorax and pulmonary hemorrhage after the localization procedure was complete. Wedge resection procedures for these PNs achieved technical success in all cases. Four patients were diagnosed with invasive adenocarcinomas and subsequently accepted lobectomy and systematic lymph node dissection. The median VATS duration and the median blood loss was 80 min and 10 mL, respectively. In total, 3, 5, and 4 PNs were respectively diagnosed as benign, mini-invasive adenocarcinomas, and invasive adenocarcinomas. CONCLUSION: Preoperative CT-guided transscapular SCN localization represents a safe, straightforward, and effective means of localizing PNs present behind the scapula.

Computed tomography-guided lung biopsy with rapid on-site evaluation for diagnosis of lung lesions: a meta-analysis.

BACKGROUND: Lung biopsy (LB) procedures performed with computed tomography (CT guidance can enable the reliable diagnosis of lung lesions. These diagnostic efforts can be further expedited through a rapid on-site evaluation (ROSE) approach, allowing for the rapid assessment of collected tissue samples to gauge the adequacy of these samples, their features, and associated cytomorphological characteristics. The present analysis was developed to examine the safety and efficacy of CT-guided LB with ROSE as a means of diagnosing lung lesions. METHODS: Studies published as of July 31, 2022 in the PubMed, Embase, and Wanfang databases were identified for this meta-analysis. Diagnostic accuracy was the primary endpoint, while secondary endpoints included the operative duration, the number of punctures, and rates of lung hemorrhage, pneumothorax, and secondary LB. RESULTS: This meta-analysis included 6 total studies. Relative to CT alone, CT with ROSE was associated with a significant increase in diagnostic accuracy (P < 0.00001). In contrast, there were no significant differences between these two groups with respect to the operative duration (P = 0.86), the number of punctures (P = 0.60), or the rates of pneumothorax (P = 0.82) or lung hemorrhage (P = 0.81). Pooled secondary LB rates were significantly lower for patients that underwent CT with ROSE relative to patients in the CT only group (P = 0.0008). Significant heterogeneity was detected for the operative duration (I2 = 94%) and number of punctures (I2 = 98%) endpoints, while no publication bias was detected for any study endpoints. CONCLUSIONS: These results suggest that ROSE may contribute to significant improvements in the diagnostic accuracy of CT-guided LB without contributing to higher rates of complications.

Bioaccumulation determines the toxicity of carbon dots to two marine dinoflagellates.

With the ever-increasing application of carbon dots (CDs), a substantial amount will be released and assemble in the aquatic environment. Nevertheless, potential photodegradation of CDs in the aquatic environment, their accumulation and impacts in aquatic organisms remain unclear. Our study examined the toxicity of CDs to two marine dinoflagellates Prorocentrum micans and Prorocentrum donghaiense. Their bioaccumulation including the uptake and elimination kinetics was also determined. Significant photodegradation of CDs in seawater was observed. Moreover, both the degraded CDs and their photodegradation products were toxic to the dinoflagellates. Although P. donghaiense was more sensitive to CDs than P. micans with the median effect concentration 17.0 and 99.0 mg L-1, respectively, such sensitivity difference disappeared when the toxicity data were plotted against cellularly accumulated CDs instead of their concentration in the experimental medium. Therefore, the higher sensitivity of P. donghaiense was attributable to its higher accumulation of CDs. Overall, the photodegradation and bioaccumulation of CDs should be considered when evaluating their environmental risks.

The First Mitochondrial Genomes of the Family Haplodiplatyidae (Insecta: Dermaptera) Reveal Intraspecific Variation and Extensive Gene Rearrangement.

Haplodiplatyidae is a recently established earwig family with over 40 species representing a single genus, Haplodiplatys Hincks, 1955. The morphology of Haplodiplatyidae has been studied in detail, but its molecular characters remain unclear. In this study, two mitogenomes of Haplodiplatys aotouensis Ma & Chen, 1991, were sequenced based on two samples from Fujian and Jiangxi provinces, respectively. These represent the first mitogenomes for the family Haplodiplatyidae. The next-generation sequencing method and subsequent automatic assembly obtained two mitogenomes. The two mitogenomes of H. aotouensis were generally identical but still exhibit a few sequence differences involving protein-coding genes (PCGs), ribosomal RNA (rRNA) genes, control regions, and intergenic spacers. The typical set of 37 mitochondrial genes was annotated, while many transfer RNA (tRNA) genes were rearranged from their ancestral locations. The calculation of nonsynonymous (Ka) and synonymous (Ks) substitution rates in PCGs indicated the fastest evolving nd4l gene in H. aotouensis. The phylogenetic analyses supported the basal position of Apachyidae but also recovered several controversial clades.

Molecular mechanisms underlying the calcium-mediated uptake of hematite nanoparticles by the ciliate Tetrahymena thermophila.

In aquatic ecosystems, the calcium (Ca) concentration varies greatly. It is well known that Ca affects the aggregation of nanoparticles (NPs) and thus their bioaccumulation. Nevertheless, Ca also plays critical roles in various biological processes, whose effects on NP accumulation in aquatic organisms remain unclear. In this study, the effects of Ca on the uptake of polyacrylate-coated hematite NPs (HemNPs) by the aquatic ciliate Tetrahymena thermophila were investigated. At all of the tested Ca concentrations, HemNPs were well dispersed in the experimental medium, excluding the possibility of Ca to influence HemNP bioaccumulation by aggregating the NPs. Instead, Ca was shown to induce the clathrin-mediated endocytosis and phagocytosis of HemNPs. Manipulation of the Ca speciation in the experimental medium as well as the influx and intracellular availability of Ca in T. thermophila indicated that HemNP uptake was regulated by the intracellular Ca level. The results of the proteomics analyses further showed that the binding of intracellular Ca to calmodulin altered the activity of proteins involved in clathrin-mediated endocytosis (calcineurin and dynamin) and phagocytosis (actin). Overall, the biologically inductive effects of Ca on NP accumulation in aquatic organisms should be considered when evaluating the environmental risks of NPs.

Photodegradation of carbon dots cause cytotoxicity.

Carbon dots (CDs) are photoluminescent nanomaterials with wide-ranging applications. Despite their photoactivity, it remains unknown whether CDs degrade under illumination and whether such photodegradation poses any cytotoxic effects. Here, we show laboratory-synthesized CDs irradiated with light degrade into molecules that are toxic to both normal (HEK-293) and cancerous (HeLa and HepG2) human cells. Eight days of irradiation photolyzes 28.6-59.8% of the CDs to <3 kilo Dalton molecules, 1431 of which are detected by high-throughput, non-target high-performance liquid chromatography-quadrupole time-of-flight mass spectrometry. Molecular network and community analysis further reveal 499 cytotoxicity-related molecules, 212 of which contain polyethylene glycol, glucose, or benzene-related structures. Photo-induced production of hydroxyl and alkyl radicals play important roles in CD degradation as affected by temperature, pH, light intensity and wavelength. Commercial CDs show similar photodegraded products and cytotoxicity profiles, demonstrating that photodegradation-induced cytotoxicity is likely common to CDs regardless of their chemical composition. Our results highlight the importance of light in cytocompatibility studies of CDs.

Perturbation of calcium homeostasis and multixenobiotic resistance by nanoplastics in the ciliate Tetrahymena thermophila.

Microplastics (MPs) are an environmental hazard of growing concern, including their potential toxic effects on the biota of different trophic levels. Nevertheless, the molecular mechanisms underlying MP-induced toxicity remain largely unknown. In the present study, Tetrahymena thermophila was exposed to polystyrene nanoplastics (PS-NPs) and the responses of this relatively sensitive ciliate were then followed using transcriptome analysis together with several other verification methods. The results showed that PS-NPs perturbed calcium (Ca) homeostasis, by inducing the inositol-1,4,5-trisphosphate-dependent liberation of Ca from the endoplasmic reticulum into the cytosol. The high cytosolic concentration of Ca induced Ca accumulation in mitochondria, which increased mitochondrial permeability and the generation of reactive oxygen species, finally leading to growth inhibition. Such toxicity is the so-called direct effects of PS-NPs. By contrast, PS-NPs also inhibited the activity of multixenobiotic resistance transporter, by down-regulating the ATP-binding cassette transporter genes Abcb15 and Abcc52. This additional effect may alter cellular responses to other pollutants and implicates PS-NPs in the risks to the organism posed by subsequent toxic exposures, which was named as the indirect effects of PS-NPs. Our study highlights the importance of considering both direct and indirect biological effects of MPs in evaluations of their environmental and health risks.

Heat stress decreases egg production of laying hens by inducing apoptosis of follicular cells via activating the FasL/Fas and TNF-α systems.

Heat stress (HS) causes significant economic losses in the poultry industry every year. However, the mechanisms for the adverse effects of HS on avian follicular development are largely unknown. The aim of this study was to test whether HS induces apoptosis of follicular cells and impairs egg production by activating the FasL/Fas and tumor necrosis factor (TNF)-α systems. To this end, Hy-Line Brown laying hens, at 32 wk of age, were either exposed to HS of 35°C to 37°C or maintained at 24°C to 26°C (control) for 5 D. At the end of the HS period, follicle numbers, apoptosis, FasL/Fas and TNF-α activation, oxidative stress, and hormone secretion were examined in ovarian follicles. Egg production was observed daily during both the stressed (day S1-S5) and the poststress recovery (day R1-R15) periods. The results demonstrated that HS on hens significantly 1) decreased laying rates from day S3 to R6; 2) reduced numbers of large yellow and hierarchical follicles; 3) triggered apoptosis while increasing the expression of FasL, Fas, TNF-α, and TNF-receptor 1 in small and large yellow follicles; and 4) increased levels of oxidative stress, corticotrophin-releasing hormone, and corticosterone while decreasing the estradiol/progesterone ratio in follicular fluid in small and large yellow follicles. Taken together, the results suggested that hen HS impaired egg production by reducing the number of follicles through inducing apoptosis and that it triggered apoptosis in follicular cells by activating the FasL/Fas and TNF-α systems.

The highly rearranged mitochondrial genomes of three economically important scale insects and the mitochondrial phylogeny of Coccoidea (Hemiptera: Sternorrhyncha).

The mitochondrial genomes (mitogenomes) of scale insects are less known in comparison to other insects, which hinders the phylogenetic and evolutionary studies of Coccoidea and higher taxa. Herein, the complete mitogenomes of Unaspis yanonensis, Planococcus citri and Ceroplastes rubens were sequenced for Coccoidea. The 15,220-bp long mitogenome of U. yanonensis contained the typical set of 37 genes including 13 PCGs, 22 tRNA genes and two rRNA genes; the 15,549-bp long mitogenome of P. citri lacked the tRNA gene trnV; the 15,387-bp long mitogenome of C. rubens exhibited several shortened PCGs and lacked five tRNA genes. The mitochondrial gene arrangement of the three mitogenomes was different from other scale insects and Drosophila yakuba. Most PCGs used standard ATN (ATA, ATT, ATC and ATG) start codons and complete TAN (TAA or TAG) termination codons. The ND4L had the highest evolutionary rate but COX1 and CYTB were the lowest. Most tRNA genes had cloverleaf secondary structures, whereas the reduction of dihydrouridine (DHU) arms and TψC arms were detected. Tandem repeats, stem-loop (SL) structures and poly-[TA]n stretch were found in the control regions (CRs) of the three mitogenomes. The phylogenetic analyses using Bayesian inference (BI) and maximum likelihood methods (ML) showed identical results, both supporting the inner relationship of Coccoidea as Coccidae + (Pseudococcidae + Diaspididae).

Mitogenomic features of the citrus leafminer, Phyllocnistis citrella (Lepidoptera: Gracillariidae) and the related mitogenomic phylogeny.

The complete mitochondrial genome of the citrus leafminer, Phyllocnistis citrella (Lepidoptera: Gracillariidae) was sequenced for the first time, which was 15,416 bp in length and with an A + T content of 81.9%. The common set of 37 genes (13 PCGs, 22 tRNA genes, and two rRNA genes) were all annotated. Most PCGs had standard ATN start codons and TAN stop codons. Most tRNA genes exhibited typical cloverleaf secondary structures, whereas the dihydrouridine (DHU) arm of trnSer (AGN) was reduced. The mitochondrial phylogenetic analyses consistently recovered the relationships within Gracillariidae.

Algal Foods Reduce the Uptake of Hematite Nanoparticles by Downregulating Water Filtration in Daphnia magna.

Rapid developments in nanotechnology have led to the release of substantial amounts of nanoparticles (NPs) into aquatic environments, where many types of biotic particles are present and could potentially interact with the NPs. Nevertheless, how biotic particles may affect the bioaccumulation and toxicity of NPs remains largely unknown. In the present study, we investigated the effects of the green alga Chlamydomonas reinhardtii on the accumulation kinetics (uptake, assimilation, efflux) and toxicity of polyacrylate-coated hematite NPs (HemNPs), using Daphnia magna as the test organism. As a biotic particle and daphnid food, C. reinhardtii reduced the accumulation and toxicity of HemNPs in D. magna. The HemNPs were well-dispersed with little adsorption to the alga. Their decreased accumulation could thus be partly explained by their low trophic transfer from the alga to the daphnid and by the inductive effects of the alga on HemNP efflux. However, the main cause was the direct inhibition of HemNP uptake from the water phase as a result of the reduced water-filtration activity of D. magna in the presence of C. reinhardtii. Overall, in bioaccumulation studies, the inhibitory effects of biotic particles on NP uptake from the water phase should be paid attention.

Complete Genome Sequence of a Class I Newcastle Disease Virus Strain Isolate from a Breeding Chicken Flock in Sichuan, China.

A Newcastle disease virus (NDV) strain, APMV-1/Chicken/China(SC)/PT3/2016, was isolated from asymptomatic chickens at a breeding farm in China. The PT3 strain has a genome length of 15,198 nucleotides and is classified as subgenotype 1b of class I. Pathogenicity tests demonstrated that PT3 is a lentogenic strain.

Waterborne and Dietborne Toxicity of Inorganic Arsenic to the Freshwater Zooplankton Daphnia magna.

Waterborne and dietborne exposure are both important sources for the accumulation of inorganic arsenic (iAs) in aquatic organisms. Although the waterborne toxicity of iAs has been extensively investigated, its dietborne toxicity has received little attention. The present study examined the acute and chronic toxicity of arsenate (iAsV) and arsenite (iAsIII) to the freshwater zooplankton species Daphnia magna under both waterborne and dietborne exposure scenarios. The bioaccumulation, speciation, and tissue and subcellular distributions of arsenic were analyzed to understand the mechanisms accounting for differences in toxicity related to different arsenic species, exposure scenarios, and exposure duration. The toxicity of iAs increased with exposure time, and iAsIII was more toxic than iAsV. Moreover, although dietborne iAs had no acute effect on D. magna, it incurred significant toxicity in the chronic-exposure experiment. Nevertheless, the toxicity of dietborne iAs was still lower than that of waterborne iAs regardless of the exposure duration. This difference was found to be caused by the lower bioaccumulation of dietborne iAs, its higher distribution in the gut and in the biologically detoxified subcellular fraction, and greater transformation to the less toxic dimethylarsinic acid. Overall, the dietborne toxicity of iAs should be considered when evaluating the environmental risks posed by arsenic.

Preparation and protective efficacy of a chicken embryo kidney cell-attenuation GI-19/QX-like avian infectious bronchitis virus vaccine.

Avian infectious bronchitis (IB) is a highly contagious disease, and hazardous to the poultry industry. Immune failure often occurs due to the emergence of new serotypes or field strains antigenically different from the vaccine strains. To prepare a candidate vaccine against the prevalent avian infectious bronchitis virus (IBV) in China, the GI-19/QX-like field isolate Sczy3 was selected as the progenitor strain and attenuated via passaging in chicken embryo kidney (CEK) cells for 100 times. The 100th generation of CEK-adapted strain, designated SczyC100, was safe to use on one-day old specific pathogen-free (SPF) chicken as determined by pathogenicity and virulence reversion test. The efficacies of SczyC100 and two commonly used commercial vaccines (H120 and 4/91) against prevalent GI-19/QX and GI-7/TWI type virulent strains were evaluated. Sczy3C100 effectively reduced the morbidity, mortality, mean lesion scores (MLSs), and viral load of trachea of chickens challenged by GI-19/QX and GI-7/TWI strains. CEK-adapted SczyC100 is therefore a potential vaccine candidate for the control of IB in China.

Isolation and molecular characterization of prevalent Fowl adenovirus strains in southwestern China during 2015-2016 for the development of a control strategy.

Fowl adenovirus (FAdV) has caused significant losses in chicken flocks throughout China in recent years. However, the current understanding of the genetic and pathogenic characteristics of the FAdV epidemic in southwestern China remains poorly understood. In this study, a total of 22 strains were isolated from liver samples of diseased chickens from farms in southwestern China. Phylogenetic analysis based on the hexon loop-1 gene showed that the 22 isolates were clustered into four distinct serotypes: FAdV serotype 4 (FAdV-4) (86.4%, 19/22), FAdV-2 (4.5%, 1/22), FAdV-8a (4.5%, 1/22), and FAdV-8b (4.5%, 1/22). FAdV-4 was the predominant serotype in southwestern China. Pathogenicity testing showed that the FAdV-4 serotype strain CH/GZXF/1602 and FAdV-8a strain CH/CQBS/1504 were pathogenic to chickens, with mortality rates reaching as high as 80% and 20%, respectively. The primary clinical feature observed following infection with strain CH/GZXF/1602 (FAdV-4) was hepatitis-hydropericardium syndrome, and that of strain CH/CQBS/1504 (FAdV-8a) was inclusion body hepatitis. Conversely, the FAdV-2 serotype strain CH/GZXF/1511 and FAdV-8b serotype strain CH/CQBS/1512 was not observed to be pathogenic in chickens. Then, CH/GZXF/1602 (FAdV-4) was selected for the preparation of an inactivated oil-emulsion vaccine. Immune studies on Partridge Shank broilers showed that a single dose immunization at 17 days of age could not only protect against homologous challenge with virulent FAdV-4 but also provided protection against clinical disease following challenge with the heterologous FAdV-8b virulent strain until 70 days of age. The characterization of newly prevalent FAdV strains provides a valuable reference for the development of an efficacious control strategy.

Genetic and antigenic evolution of H9N2 subtype avian influenza virus in domestic chickens in southwestern China, 2013-2016.

H9N2 avian influenza virus (AIV) has caused significant losses in chicken flocks throughout china in recent years. There is a limited understanding of the genetic and antigenic characteristics of the H9N2 virus isolated in chickens in southwestern China. In this study a total of 12 field strains were isolated from tissue samples from diseased chickens between 2013 and 2016. Phylogenetic analysis of the Hemagglutinin (HA) and Neuraminidase (NA) nucleotide sequences from the 12 field isolates and other reference strains showed that most of the isolates in the past four years could be clustered into a major branch (HA-branch A and NA-branch I) in the Clade h9.4.2 lineages. These sequences are accompanied by nine and seven new amino acids mutations in the HA and NA proteins, respectively, when compared with those previous to 2013. In addition, four new isolates were grouped into a minor branch (HA-branch B) in the Clade h9.4.2 lineages and two potential N-glycosylation sites were observed due to amino acid mutations in the HA protein. Three antigenic groups (1-3), which had low antigenic relatedness with two commonly used vaccines in China, were identified among the 12 isolates by antigenMap analysis. Immunoprotection testing showed that those two vaccines could efficiently prevent the shedding of branch A viruses but not branch B viruses. In conclusion, these results indicate the genotype of branch B may become epidemic in the next few years and that a new vaccine should be developed for the prevention of H9N2 AIV.