Estimating the time of infection for African swine fever in pig farms in Korea

African swine fever (ASF) is a highly contagious and lethal disease with characteristics of hemorrhagic fever. ASF outbreaks in pig farms significantly damage the entire pork industry. Understanding the transmission dynamics of ASF is crucial to effectively respond. Notably, it is important to know when the infection started on the outbreak farm. This study aimed at establishing a procedure for estimating the time of infection on pig farms affected by the ASF outbreak in Korea. The protocol for sampling to detect ASF virus infection, the estimation of the time interval between infection and detection, and the estimation of the infection stage parameters for the simulation model were described. After infection, fattening sheds (9.8 days in median) had the longest detection time compared with pregnant (8.6 days) or farrowing sheds (8.0 days). The intervals were 8.8 days for farrow-to-finisher farms, 7.0 days for farrow-to-weaning farms, and 9.5 days for fattening farms. The findings of this study provide valuable insights into ASF outbreaks in pig farms thus, improving the disease control ability

Effects of HA and NA glycosylation pattern changes on the transmission of avian influenza A(H7N9) virus in guinea pigs

AbstractAvian influenza H7N9 virus has posed a concern of potential human-to-human transmission by resulting in seasonal virus-like human infection cases. To address the issue of sustained human infection with the H7N9 virus, here we investigated the effects of hemagglutinin (HA) and neuraminidase (NA) N-linked glycosylation (NLG) patterns on influenza virus transmission in a guinea pig model. Based on the NLG signatures identified in the HA and NA genetic sequences of H7N9 viruses, we generated NLG mutant viruses using either HA or NA gene of a H7N9 virus, A/Anhui/01/2013, by reverse genetics on the 2009 pandemic H1N1 virus backbone. For the H7 HA NLG mutant viruses, NLG pattern changes appeared to reduce viral transmissibility in guinea pigs. Intriguingly, however, the NLG changes in the N9 NA protein, such as a removal from residue 42 or 66 or an addition at residue 266, increased transmissibility of the mutant viruses by more than 33%, 50%, and 16%, respectively, compared with a parental N9 virus. Given the effects of HA-NA NLG changes with regard to viral transmission, we then generated the HA-NA NLG mutant viruses harboring the H7 HA of double NLG addition and the N9 NA of various NLG patterns. As seen in the HA NLG mutants above, the double NLG-added H7 HA decreased viral transmissibility. However, when the NA NLG changes occurred by a removal of residue 66 and an addition at 266 were additionally accompanied, the HA-NA NLG mutant virus recovered the transmissibility of its parental virus. These demonstrate the effects of specific HA-NA NLG changes on the H7N9 virus transmission by highlighting the importance of a HA-NA functional balance

Genome-Wide Association Study for Ultraviolet-B Resistance in Soybean (<i>Glycine max</i> L.)

The depletion of the stratospheric ozone layer is a major environmental issue and has increased the dosage of ultraviolet-B (UV-B) radiation reaching the Earth’s surface. Organisms are negatively affected by enhanced UV-B radiation, and especially in crop plants this may lead to severe yield losses. Soybean (Glycine max L.), a major legume crop, is sensitive to UV-B radiation, and therefore, it is required to breed the UV-B-resistant soybean cultivar. In this study, 688 soybean germplasms were phenotyped for two categories, Damage of Leaf Chlorosis (DLC) and Damage of Leaf Shape (DLS), after supplementary UV-B irradiation for 14 days. About 5% of the germplasms showed strong UV-B resistance, and GCS731 was the most resistant genotype. Their phenotypic distributions showed similar patterns to the normal, suggesting UV-B resistance as a quantitative trait governed by polygenes. A total of 688 soybean germplasms were genotyped using the Axiom® Soya 180K SNP array, and a genome-wide association study (GWAS) was conducted to identify SNPs significantly associated with the two traits, DLC and DLS. Five peaks on chromosomes 2, 6, 10, and 11 were significantly associated with either DLC or DLS, and the five adjacent genes were selected as candidate genes responsible for UV-B resistance. Among those candidate genes, Glyma.02g017500 and Glyma.06g103200 encode cryptochrome (CRY) and cryptochrome 1 (CRY1), respectively, and are known to play a role in DNA repair during photoreactivation. Real-time quantitative RT-PCR (qRT-PCR) results revealed that CRY1 was expressed significantly higher in the UV-B-resistant soybean compared to the susceptible soybean after 6 h of UV-B irradiation. This study is the first GWAS report on UV-B resistance in soybean, and the results will provide valuable information for breeding UV-B-resistant soybeans in preparation for climate change

Potentiation of Sodium Metabisulfite Toxicity by Propylene Glycol in Both in Vitro and in Vivo Systems

Many consumer products used in our daily lives result in inhalation exposure to a variety of chemicals, although the toxicities of the active ingredients are not well known; furthermore, simultaneous exposure to chemical mixtures occurs. Sodium metabisulfite (SM) and propylene glycol (PG) are used in a variety of products. Both the cytotoxicity and the sub-acute inhalation toxicity of each chemical and their mixtures were evaluated. Assays for cell viability, membrane damage, and lysosome damage demonstrated that SM over 100 μg/ml induced significant cytotoxicity; moreover, when PG, which was not cytotoxic, was mixed with SM, the cytotoxicity of the mixture was enhanced. Solutions of 1, 5, and 20% SM, each with 1% PG solution, were prepared, and the whole body of rats was exposed to aerosols of the mixture for 6 h/day, 5 days/week for 2 weeks. The rats were sacrificed 1 (exposure group) or 7 days (recovery group) after termination of the exposure. The actual concentration of SM in the low-, medium-, and high-exposure groups was 3.91 ± 1.26, 35.73 ± 6.01, and 80.98 ± 5.47 mg/m3, respectively, and the actual concentration of PG in each group was 6.47 ± 1.25, 8.68 ± 0.6, and 8.84 ± 1.77 mg/m3. The repeated exposure to SM and PG caused specific clinical signs including nasal sound, sneeze, and eye irritation which were not found in SM single exposure. In addition, the body weight of treatment group rats decreased compared to that of the control group rats in a time-dependent manner. The total protein concentration and lactate dehydrogenase activity in the bronchoalveolar lavage fluid (BALF) increased. Histopathological analysis of the lungs, liver, and nasal cavity was performed. Adverse effects were observed in the nasal cavity, with squamous cell metaplasia identified in the front of the nasal cavity in all high-exposure groups, which completely recovered 7 days after exposure was terminated. Whereas inhalation of SM for 2 weeks only reduced body weight in the high-dose group, inhalation of SM and PG mixtures for 2 weeks significantly decreased body weight and induced metaplasia of the respiratory epithelium into squamous cells in the medium- and high-dose groups. In conclusion, PG potentiated the toxicity of SM in human lung epithelial cells and the inhalation toxicity in rats

In Vitro and In Vivo Evaluation of the Toxic Effects of Dodecylguanidine Hydrochloride

The toxicity profiles of the widely used guanidine-based chemicals have not been fully elucidated. Herein, we evaluated the in vitro and in vivo toxicity of eight guanidine-based chemicals, focusing on inhalation toxicity. Among the eight chemicals, dodecylguanidine hydrochloride (DGH) was found to be the most cytotoxic (IC50: 0.39 &mu;g/mL), as determined by the water soluble tetrazolium salts (WST) assay. An acute inhalation study for DGH was conducted using Sprague-Dawley rats at 8.6 &plusmn; 0.41, 21.3 &plusmn; 0.83, 68.0 &plusmn; 3.46 mg/m3 for low, middle, and high exposure groups, respectively. The levels of lactate dehydrogenase, polymorphonuclear leukocytes, and cytokines (MIP-2, TGF-&beta;1, IL-1&beta;, TNF-&alpha;, and IL-6) in the bronchoalveolar lavage fluid increased in a concentration-dependent manner. Histopathological examination revealed acute inflammation with necrosis in the nasal cavity and inflammation around terminal bronchioles and alveolar ducts in the lungs after DGH inhalation. The LC50 of DGH in rats after exposure for 4 h was estimated to be &gt;68 mg/m3. Results from the inhalation studies showed that DGH was more toxic in male rats than in female rats. Overall, DGH was found to be the most cytotoxic chemical among guanidine-based chemicals. Exposure to aerosols of DGH could induce harmful pulmonary effects on human health

Genome-Wide Analysis of Human Metapneumovirus Evolution

<div><p>Human metapneumovirus (HMPV) has been described as an important etiologic agent of upper and lower respiratory tract infections, especially in young children and the elderly. Most of school-aged children might be introduced to HMPVs, and exacerbation with other viral or bacterial super-infection is common. However, our understanding of the molecular evolution of HMPVs remains limited. To address the comprehensive evolutionary dynamics of HMPVs, we report a genome-wide analysis of the eight genes (N, P, M, F, M2, SH, G, and L) using 103 complete genome sequences. Phylogenetic reconstruction revealed that the eight genes from one HMPV strain grouped into the same genetic group among the five distinct lineages (A1, A2a, A2b, B1, and B2). A few exceptions of phylogenetic incongruence might suggest past recombination events, and we detected possible recombination breakpoints in the F, SH, and G coding regions. The five genetic lineages of HMPVs shared quite remote common ancestors ranging more than 220 to 470 years of age with the most recent origins for the A2b sublineage. Purifying selection was common, but most protein genes except the F and M2-2 coding regions also appeared to experience episodic diversifying selection. Taken together, these suggest that the five lineages of HMPVs maintain their individual evolutionary dynamics and that recombination and selection forces might work on shaping the genetic diversity of HMPVs.</p></div

Adaptive mutations of neuraminidase stalk truncation and deglycosylation confer enhanced pathogenicity of influenza A viruses

Abstract It has been noticed that neuraminidase (NA) stalk truncation has arisen from evolutionary adaptation of avian influenza A viruses (IAVs) from wild aquatic birds to domestic poultry. We identified this molecular alteration after the adaptation of a 2009 pandemic H1N1 virus (pH1N1) in BALB/c mice. The mouse-adapted pH1N1 lost its eight consecutive amino acids including one potential N-linked glycosite from the NA stalk region. To explore the relationship of NA stalk truncation or deglycosylation with viral pathogenicity changes, we generated NA stalk mutant viruses on the pH1N1 backbone by reverse genetics. Intriguingly, either NA stalk truncation or deglycosylation changed pH1N1 into a lethal virus to mice by resulting in extensive pathologic transformation in the mouse lungs and systemic infection affecting beyond the respiratory organs in mice. The increased pathogenicity of these NA stalk mutants was also reproduced in ferrets. In further investigation using a human-infecting H7N9 avian IAV strain, NA stalk truncation or deglycosylation enhanced the replication property and pathogenicity of H7N9 NA stalk mutant viruses in the same mouse model. Taken together, our results suggest that NA stalk truncation or deglycosylation can be the pathogenic determinants of seasonal influenza viruses associated with the evolutionary adaptation of IAVs

Population dynamics of HMPV sequences in skyline reconstruction plots.

<p>The demographic inferences of HMPV genetic diversity were depicted using a Bayesian skyline reconstruction plot method. The plots for the eight genes were then reconstituted into the five lineages. Solid lines represent mean diversity, and dotted lines represent the lower and upper limits of the 95% HPD.</p