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ABSTRACT: This study aimed to explore the probiotic characteristics of Lacticaseibacillus rhamnosus SN21-1 and Lactiplantibacillus plantarum SN21-2 by genotype and phenotype analysis, assess their safety in vitro and in vivo, and investigate the effects of L. rhamnosus SN21-1 and L. plantarum SN21-2 on Salmonella typhimurium-infected broilers in an in vivo experiment. L. rhamnosus SN21-1 and L. plantarum SN21-2 showed antimicrobial activity against pathogens, including S. Typhimurium, resistance to simulated gastrointestinal digestive fluid, and adhesion to HT-29 cells. In addition, L. rhamnosus SN21-1 and L. plantarum SN21-2 showed no resistance to most common antimicrobial agents and no haemolysis in vitro. Whole-genome sequence analyses of L. rhamnosus SN21-1 and L. plantarum SN21-2 provided basic genomic information, functional genes underlying the probiotic characteristics, and evidence of safety. Furthermore, feeding with L. rhamnosus SN21-1 or L. plantarum SN21-2 for 28 d had no significant effect on the growth or blood biochemical parameters of the broilers, and hematoxylin-eosin staining revealed no liver, spleen, heart, or kidney damage. Additionally, L. rhamnosus SN21-1 or L. plantarum SN21-2 did not translocate to the blood, liver, spleen, heart, or kidney of the broilers. Moreover, L. rhamnosus SN21-1 and L. plantarum SN21-2 significantly reduced S. Typhimurium counts in the faeces and caecal contents of S. Typhimurium-infected broilers and reduced small intestinal bleeding in S. Typhimurium-infected broilers. Consequently, L. rhamnosus SN21-1 and L. plantarum SN21-2 have excellent probiotic characteristics and are safe for use as anti-S. typhimurium probiotics in broilers.

Abstract Background Coccidioidomycosis is a systemic infection caused by dimorphic fungi Coccidioides spp. endemic to Southwestern United States and Central and South America. A history of residence and travel in these areas is essential for the diagnostic of coccidioidomycosis, which has highly variable symptoms ranging from asymptomatic to severe, disseminated infection, and even death. Immunocompromised patients of coccidioidomycosis experience a high risk of dissemination, chronic infection, and mortality. Meningitis is one of the most deleterious coccidioidomycosis and can cause various life-threatening complications. Case presentation Here we report a case of Coccidioides posadasii meningitis in a 49-year-old female who returned to China after one and a half years residence in Los Angeles, USA. The repeated routine cultures using CSF for bacteria or fungi were all negative. To hunt for an infectious etiology, the state-of-the-art technology metagenomic next-generation sequencing (mNGS) was then utilized, suggesting Coccidioides posadasii. Organizational pathological examination and polymerase-chain-reaction (PCR) results subsequently confirmed the mNGS detection. Conclusion To our knowledge, cases for coccidioidal meningitis have been rarely reported in China. While global travelling may spread this disease across continents and make the diagnosis more difficult. mNGS can detect almost all known pathogens with high sensitivity and specificity, especially for uncommon pathogen, such as Coccidioides posadasii in China.

The display of full-length antibody on the cell surface was achieved by fusing a transmembrane domain of the platelet-derived growth factor receptor (PDGFR) to the C-terminus of the heavy chain constant region. We also incorporated a furin cleavage site between the constant region and PDGFR transmembrane domain to obtain secreted antibodies. As a result, antibodies can be expressed simultaneously on the cell surface in a membrane-anchored version for screening and selecting through fluorescence-activated cell sorting (FACS) analysis, as well as in conditioned medium in a secreted version for function analysis.

Pseudomonas protegens can serve as an agricultural biocontrol agent. P. protegens often encounters hyperosmotic stress during industrial production and fi eld application. The ability of P. protegens to withstand hyperosmotic stress is important for its application as a biocontrol agent. AlgU is a global regulator responsible for stress response and biocontrol ability. However, the specific regulatory role of AlgU in the hyperosmotic adaptation of P. protegens is poorly understood. In this study, we found that the AlgU mutation disrupted the hyperosmotic tolerance of P. protegens. Many genes and metabolites related to cell envelope formation were significantly downregulated in ΔalgU compared with that in the wild-type (WT) strain under hyperosmotic conditions, and we found that the algU mutation caused membrane integrity to be compromised and increased membrane permeability. Further experiments revealed that the cell envelope integrity protein TolA, which is regulated by AlgU, contributes to cell membrane stability and osmotic tolerance in P. protegens. In addition, several genes related to oxidative stress response were significantly downregulated in ΔalgU, and higher levels of intracellular reactive oxygen species were found in ΔalgU. Furthermore, we found that the synthesis of N-acetyl glutaminyl glutamine amide is directly regulated by AlgU and contributes to the hyperosmotic adaptation of P. protegens. This study revealed the mechanisms of AlgU's participation in osmotic tolerance in P. protegens, and it provides potential molecular targets for research on the hyperosmotic adaptation of P. protegens. [ABSTRACT FROM AUTHOR]