Phthalic Acid Esters: Natural Sources and Biological Activities

Phthalic acid esters (PAEs) are a class of lipophilic chemicals widely used as plasticizers and additives to improve various products’ mechanical extensibility and flexibility. At present, synthesized PAEs, which are considered to cause potential hazards to ecosystem functioning and public health, have been easily detected in the atmosphere, water, soil, and sediments; PAEs are also frequently discovered in plant and microorganism sources, suggesting the possibility that they might be biosynthesized in nature. In this review, we summarize that PAEs have not only been identified in the organic solvent extracts, root exudates, and essential oils of a large number of different plant species, but also isolated and purified from various algae, bacteria, and fungi. Dominant PAEs identified from natural sources generally include di-n-butyl phthalate, diethyl phthalate, dimethyl phthalate, di(2-ethylhexyl) phthalate, diisobutyl phthalate, diisooctyl phthalate, etc. Further studies reveal that PAEs can be biosynthesized by at least several algae. PAEs are reported to possess allelopathic, antimicrobial, insecticidal, and other biological activities, which might enhance the competitiveness of plants, algae, and microorganisms to better accommodate biotic and abiotic stress. These findings suggest that PAEs should not be treated solely as a “human-made pollutant” simply because they have been extensively synthesized and utilized; on the other hand, synthesized PAEs entering the ecosystem might disrupt the metabolic process of certain plant, algal, and microbial communities. Therefore, further studies are required to elucidate the relevant mechanisms and ecological consequences

Research Note: Genetic characterization and pathogenicity of an epidemic variant strain of avian reovirus

ABSTRACT: The past few years have witnessed a rapid increase in cases of viral arthritis caused by avian reovirus (ARV) in chicken farms in China, attributed to the emergence of variant strains that render traditional vaccines ineffective, leading to substantial economic losses. In this study, we successfully isolated a novel ARV strain, designated as 2023ARV-GS-SDAU-1, from chickens in a broiler flock vaccinated with an ARV vaccine in Gansu province. We performed whole-genome sequencing and assessed its pathogenicity through 2 infection routes: oral administration and intraperitoneal injection. Our analysis revealed significant variations in the σA gene, associated with the inhibition of interferon secretion, compared to known ARV strains. The highest nucleotide identity observed was below 80%. Additionally, the σC gene exhibited notable variations compared to its homologous strains within the same group. Multiple alignment of the amino acid sequences classified the 2023ARV-GS-SDAU-1 strain under genotype I. Furthermore, our pathogenicity experiments indicated that the isolated strain exhibited more severe pathogenicity when administered via intraperitoneal injection in SPF chickens. In summary, our data suggest that the 2023ARV-GS-SDAU-1 strain represents a novel variant circulating in broiler flocks in China. These findings enrich currently available genetic information on ARV strains and provide a new complete genome sequence

Molecular characteristics and pathogenicity of a novel chicken astrovirus variant

Abstract It is well-established that the genetic diversity, regional prevalence, and broad host range of astroviruses significantly impact the poultry industry. In July 2022, a small-scale commercial broiler farm in China reported cases of growth retardation and a 3% mortality rate. From chickens displaying proventriculitis and pancreatitis, three chicken astroviruses (CAstV) isolates were obtained and named SDAU2022-1-3. Complete genomic sequencing and analysis revealed the unique characteristics of these isolates from known CAstV strains in ORF1a, ORF1b, and ORF2 genes, characterized by an unusually high variability. Analysis of amino acid mutations in ORF1a, ORF1b, and ORF2 indicated that the accumulation of these mutations played a pivotal role in the emergence of the variant strain. Inoculation experiments demonstrated that affected chickens exhibited liver and kidney enlargement, localized proventricular hemorrhage, and a dark reddish-brown appearance in about two-thirds of the pancreas. Histopathological examination unveiled hepatic lymphocytic infiltration, renal tubular epithelial cell swelling, along with lymphocytic proventriculitis and pancreatitis. Quantitative reverse transcription-polymerase chain reaction (qRT-PCR) analysis indicated viremia and viral shedding at 3 days post-infection (dpi). The proventriculus displayed the highest viral loads, followed by the liver, kidney, duodenum, and pancreas. Liver parameters (AST and ALT) and kidney parameters (UA and UN) demonstrated mild damage consistent with earlier findings. While the possibility of new mutations in the ORF2 gene of CAstV causing proventriculitis and pancreatitis warrants further investigation, these findings deepen our comprehension of CAstV’s pathogenicity in chickens. Additionally, they serve as valuable references for subsequent research endeavors