Objective: To investigate the distribution characteristics of ABO and Rh blood group antigen phenotypes among blood donors in the Yantai, Shandong. Methods: Blood samples from 310 180 voluntary blood donors in Yantai collected from January 2019 to December 2023 were tested for ABO and Rh blood group antigens using standard serological methods. RhD-negative samples were further typed for C, c, E, and e antigens. Population genetic analysis of blood groups was performed: allele frequencies were inferred from ABO phenotypes, and Rh allele/haplotype frequencies were estimated based on the proportion of RhD-negative donors and CcEe antigen typing, followed by Hardy-Weinberg equilibrium testing. Results: The phenotypic distribution frequency of ABO blood groups was B(32.72%)>O(28.93%)>A(27.65%)>AB(10.70%). The inferred allele frequencies were r(53.74%)>q(24.78%)>p(21.48%), consistent with Hardy-Weinberg equilibrium (P>0.05). A total of 1 872 Rh-negative donors (0.603%) were identified. The most common Rh phenotypes were ccdee (59.56%) and Ccdee (30.18%). The distribution of Rh antigen phenotypes deviated significantly from Hardy-Weinberg equilibrium (χ =37.15, P<0.001), with the cde haplotype showing the highest frequency. There was no statistically significant difference in ABO blood group distribution between RhD-positive and RhD-negative donors (P>0.05). Conclusion: The ABO blood group distribution among voluntary blood donors in Yantai is generally stable and consistent with population genetic equilibrium, whereas the Rh antigen phenotype distribution deviates from equilibrium, indicating potential underlying genetic structural differences.

A Salmonella bacteriophage,PJN025,was isolated from wastewater and characterized for its biological properties,including whole-genome sequencing and assessment of therapeutic poten-tial in animal infection models.Transmission electron microscopy classified it within the Caudovi-ricetes family.PJN025 selectively lysed S.typhimurium and S.enteritidis with an incubation period of approximately 10 min,a burst time of 80 min,and an average burst size of approximately 132 PFU/cell,demonstrating effective bactericidal activity.The phage showed robust stability at temperatures ranging from 30 to 70 ℃ and pH levels from 3 to 12.Whole-genome sequencing re-vealed a complete genome length of 46 478 bp with a G+C content of 45.9％,consisting of 82 open reading frames and one tRNA.No known virulence or resistance genes were found.In Galleria mellonella infection model,a survival rate of 70％was achieved with a preventative dose of 1 × 108 PFU/mL PJN025,compared to a 5％survival rate in the positive control group after 48 h of bacterial challenge.In SPF mice infected with S.typhimurium via intraperitoneal injection,all mices in the positive control group died within five days.However,in the co-infection group treated with 1×108 PFU/mL PJN025,a promising survival rate of 60％was observed.This study showed that the bacteriophage PJN025 had strong specificity,high lytic efficiency,good acid and alkali tol-erance,strong heat resistance,and good safety and prevention effects,providing materials and ex-perimental basis for the development of subsequent phage products.

A Salmonella bacteriophage,PJN025,was isolated from wastewater and characterized for its biological properties,including whole-genome sequencing and assessment of therapeutic poten-tial in animal infection models.Transmission electron microscopy classified it within the Caudovi-ricetes family.PJN025 selectively lysed S.typhimurium and S.enteritidis with an incubation period of approximately 10 min,a burst time of 80 min,and an average burst size of approximately 132 PFU/cell,demonstrating effective bactericidal activity.The phage showed robust stability at temperatures ranging from 30 to 70 ℃ and pH levels from 3 to 12.Whole-genome sequencing re-vealed a complete genome length of 46 478 bp with a G+C content of 45.9％,consisting of 82 open reading frames and one tRNA.No known virulence or resistance genes were found.In Galleria mellonella infection model,a survival rate of 70％was achieved with a preventative dose of 1 × 108 PFU/mL PJN025,compared to a 5％survival rate in the positive control group after 48 h of bacterial challenge.In SPF mice infected with S.typhimurium via intraperitoneal injection,all mices in the positive control group died within five days.However,in the co-infection group treated with 1×108 PFU/mL PJN025,a promising survival rate of 60％was observed.This study showed that the bacteriophage PJN025 had strong specificity,high lytic efficiency,good acid and alkali tol-erance,strong heat resistance,and good safety and prevention effects,providing materials and ex-perimental basis for the development of subsequent phage products.