Objective We aimed to investigate the effects of different non-surgical embryo transfer devices,number of transferred embryos,embryo stage,and embryos obtained from different mouse strains on the efficiency of non-surgical embryo transfer in mice,and to compare the efficiencies of surgical and non-surgical embryo transfer,in order to establish a stable non-surgical embryo transfer technology system.Methods Mouse embryo transfer was carried out using non-surgical method.Results The pregnancy rates using two different non-surgical transfer devices were(75.00±0.00)％and(66.67±14.43)％,and the birth rates were(46.11±6.31)％and(18.89±0.96)％,respectively.Transfer of 10,15,and 20 embryos resulted in pregnancy rates of(66.67±11.55)％,(80.00±0.00)％,and(66.67±23.09)％,and birth rates of(29.33±4.16)％,(38.67±4.81)％,and(17.00±3.46)％,respectively.When blastocysts and morulae were transferred non-surgically,the resulting pregnancy rates were(80.00±0.00)％and(46.67±11.55)％and the birth rates were(38.67±4.81)％and(10.22±2.77)％,respectively.Four strains(C57BL/6J,ICR,genetically modified mice A,genetically modified mice B)were used as donors for non-surgical embryo transfer,with resulting pregnancy rates of(66.67±11.55)％,(80.00±0.00)％,(73.33±11.55)％,and(80.00±0.00)％,and birthrates of(26.67±2.67)％,(38.67±4.81)％,(32.00±3.53)％,and(29.34±2.31)％,respectively.Fifteen pseudo-pregnant mice were transplanted surgically and 15 were transplanted non-surgically,with pregnancy rates of(80.00±0.00)％and(86.67±11.55)％,and birth rates of(38.67±4.81)％and(36.00±5.82)％,respectively.Conclusions Transfer device A resulted in a higher birth rate in this study.The embryo transfer efficiency was higher when 15 embryos were transferred into unilateral uterine horns of pseudo-pregnant 2.5-day recipients.Blastocyst-stage embryo transfer was more efficient than morula-stage transfer.There was no significant difference in efficiency between surgical and non-surgical embryo transfer procedures.

As an important and fundamental resource of scientific research,laboratory animals have become essential tools for the continuous advancements in life sciences,medical research,drug development,and other fields.With the development of related laws and regulations,the welfare of laboratory animals is increasingly valued by the general public and international research communities alike.To ensure the welfare of laboratory animals,the ethical review and conduct of laboratory animal practitioners should be standardized,incorporating and adapting advanced international practices with those in China.This article primarily outlines the process for reviewing and approving animal use protocols,along with the standards for evaluation,with the aim of providing a reference for researchers writing animal use protocols and for International Animal Care and Use Committee members conducting ethical reviews of laboratory animal welfare.

Objective To establish a rapid and accurate droplet digital PCR(ddPCR)detection method for detecting Staphylococcus aureus(SA)in laboratory animals and the environment.Methods Using the heat-stable nuclease gene(nuc)of SA as the target gene,a pair of specific primers and probes are designed within its conserved region.Optimize the reaction conditions,test the dynamic range,and evaluate the specificity and stability of the method.Using the same template,test reactions were performed with both ddPCR and real-time quantitative PCR(qPCR)method to assess the interchangeability between the two approaches.Finally,the method is applied to the detection of various clinical samples.Results The kinetic range of the established SA ddPCR method is 100～15 000 copies/μL,with a detection limit of 2.5 copies and a quantification limit of 10 copies;The specificity of this method was tested,and only SA showed positive droplets,while no positive droplets were found for other pathogens;After measuring three parallel samples,the standard deviation and relative standard deviation were calculated.It was found that within the dynamic detection interval of ddPCR,as the target copy number gradually decreased,the relative standard deviation showed an upward trend,but remained below 25％.This result indicates that the detection method has good stability.Conclusions The established ddPCR method for detecting SA has the advantages of high sensitivity,strong specificity,good stability,and good reproducibility.This method can be applied for the detection of SA in laboratory animals.

Objective To establish a rapid and accurate droplet digital PCR(ddPCR)detection method for detecting Staphylococcus aureus(SA)in laboratory animals and the environment.Methods Using the heat-stable nuclease gene(nuc)of SA as the target gene,a pair of specific primers and probes are designed within its conserved region.Optimize the reaction conditions,test the dynamic range,and evaluate the specificity and stability of the method.Using the same template,test reactions were performed with both ddPCR and real-time quantitative PCR(qPCR)method to assess the interchangeability between the two approaches.Finally,the method is applied to the detection of various clinical samples.Results The kinetic range of the established SA ddPCR method is 100～15 000 copies/μL,with a detection limit of 2.5 copies and a quantification limit of 10 copies;The specificity of this method was tested,and only SA showed positive droplets,while no positive droplets were found for other pathogens;After measuring three parallel samples,the standard deviation and relative standard deviation were calculated.It was found that within the dynamic detection interval of ddPCR,as the target copy number gradually decreased,the relative standard deviation showed an upward trend,but remained below 25％.This result indicates that the detection method has good stability.Conclusions The established ddPCR method for detecting SA has the advantages of high sensitivity,strong specificity,good stability,and good reproducibility.This method can be applied for the detection of SA in laboratory animals.

Objective We aimed to investigate the effects of different non-surgical embryo transfer devices,number of transferred embryos,embryo stage,and embryos obtained from different mouse strains on the efficiency of non-surgical embryo transfer in mice,and to compare the efficiencies of surgical and non-surgical embryo transfer,in order to establish a stable non-surgical embryo transfer technology system.Methods Mouse embryo transfer was carried out using non-surgical method.Results The pregnancy rates using two different non-surgical transfer devices were(75.00±0.00)％and(66.67±14.43)％,and the birth rates were(46.11±6.31)％and(18.89±0.96)％,respectively.Transfer of 10,15,and 20 embryos resulted in pregnancy rates of(66.67±11.55)％,(80.00±0.00)％,and(66.67±23.09)％,and birth rates of(29.33±4.16)％,(38.67±4.81)％,and(17.00±3.46)％,respectively.When blastocysts and morulae were transferred non-surgically,the resulting pregnancy rates were(80.00±0.00)％and(46.67±11.55)％and the birth rates were(38.67±4.81)％and(10.22±2.77)％,respectively.Four strains(C57BL/6J,ICR,genetically modified mice A,genetically modified mice B)were used as donors for non-surgical embryo transfer,with resulting pregnancy rates of(66.67±11.55)％,(80.00±0.00)％,(73.33±11.55)％,and(80.00±0.00)％,and birthrates of(26.67±2.67)％,(38.67±4.81)％,(32.00±3.53)％,and(29.34±2.31)％,respectively.Fifteen pseudo-pregnant mice were transplanted surgically and 15 were transplanted non-surgically,with pregnancy rates of(80.00±0.00)％and(86.67±11.55)％,and birth rates of(38.67±4.81)％and(36.00±5.82)％,respectively.Conclusions Transfer device A resulted in a higher birth rate in this study.The embryo transfer efficiency was higher when 15 embryos were transferred into unilateral uterine horns of pseudo-pregnant 2.5-day recipients.Blastocyst-stage embryo transfer was more efficient than morula-stage transfer.There was no significant difference in efficiency between surgical and non-surgical embryo transfer procedures.

As an important and fundamental resource of scientific research,laboratory animals have become essential tools for the continuous advancements in life sciences,medical research,drug development,and other fields.With the development of related laws and regulations,the welfare of laboratory animals is increasingly valued by the general public and international research communities alike.To ensure the welfare of laboratory animals,the ethical review and conduct of laboratory animal practitioners should be standardized,incorporating and adapting advanced international practices with those in China.This article primarily outlines the process for reviewing and approving animal use protocols,along with the standards for evaluation,with the aim of providing a reference for researchers writing animal use protocols and for International Animal Care and Use Committee members conducting ethical reviews of laboratory animal welfare.

To screen and identify the key host proteins interacting with the non-structural protein 15 (Nsp15) of porcine epidemic diarrhea virus (PEDV). The IP/pull-down assay and mass spectrometry were employed to screen and identify the host proteins interacting with Nsp15. The interaction between the host protein and Nsp15 was studied by co-immunoprecipitation and laser scanning confocal microscopy. Finally, Western blotting and RT-qPCR were employed to examine the interaction between SLC25a3 and PEDV. The recombinant eukaryotic expression vector pcDNA3.1(+)-Flag-Nsp15 was successfully constructed, and the host protein SLC25a3 interacting with PEDV Nsp15 was screened out. An interaction existed between SLC25a3 and Nsp15, and SLC25a3 significantly inhibited PEDV replication in a dose-dependent manner. SLC25a3 inhibits PEDV replication. The results of this study provide a basis for deciphering the role and mechanism of SLC25a3 in the host immune response to PEDV infection.
Porcine epidemic diarrhea virus/genetics* ; Viral Nonstructural Proteins/metabolism* ; Animals ; Swine ; Virus Replication ; Coronavirus Infections/veterinary* ; Swine Diseases/metabolism*

Feces and intestinal contents of pigs suspected with porcine epidemic diarrhea virus were collected from a farm in Minqin County,Gansu Province,China.After the suspected positive sam-ples were detected by RT-PCR,Vero cells were used to isolate and culture them in vitro.The suc-cessfully isolated virus was identified in the laboratory,and its whole genome sequence was ana-lyzed for genetic evolution.The pathogenicity was evaluated by animal regression test.The results showed that typical syncytial lesions could be observed when the PEDV-positive treatment solu-tion was inoculated with Vero cells in the 4th generation,and the virus titer in the 6th generation reached 10-4 75TCID50/mL.PEDV-like virions with a diameter of about 100 nm and a round shape with obvious capsular membranes and spikes were observed by electron microscopy.Whole genome sequencing analysis showed that the total length of this strain was 28 085 bp,which was far from the G1 subtype represented by the classical strain CV777(96.6％),and had a high homology with the G2b strains BC-2011-1,IA1,USA/Colorado/2013 and WELL(98.6％).This indicated that the strain belonged to the G2b epidemic strain.The animal regression test showed that the 5-day-old piglets developed vomiting,acute watery diarrhea,emaciation and mental depression within 12 h after the attack,and the symptoms worsened and died within 24 h.After autopsy,the infected piglets could be observed with stomach swelling,high intestinal heave,thin and transparent intesti-nal wall,and undigested milk clots inside.In summary,a PEDV G2b epidemic strain was success-fully isolated and identified in this study,and its whole genome sequence and pathogenicity were analyzed,providing research materials for future studies on PEDV gene function,pathogenic mech-anism and vaccine development.

Improving the reproducibility of biomedical research results is a major challenge.Transparent and accurate reporting of the research process enables readers to evaluate the reliability of the research results and further explore the experiment by repeating it or building upon its findings. The ARRIVE 2.0 guidelines, released in 2019 by the UK National Centre for the Replacement, Refinement and Reduction of Animals in Research (NC3Rs), provide a checklist applicable to any in vivo animal research report. These guidelines aim to improve the standardization of experimental design, implementation, and reporting, as well as the reliability, repeatability, and clinical translatability of animal experimental results. The use of ARRIVE 2.0 guidelines not only enriches the details of animal experimental research reports, ensuring that information on animal experimental results is fully evaluated and utilized, but also enables readers to understand the content expressed by the author accurately and clearly, promoting the transparency and integrity of the fundamental research review process. At present, the ARRIVE 2.0 guidelines have been widely adopted by international biomedical journals. This article is a Chinese translation based on the best practices of international journals following the ARRIVE 2.0 guidelines in international journals, specifically for the complete interpretation of the ARRIVE 2.0 guidelines published in the PLoS Biology journal in 2020 (original text can be found at https://arriveguidelines.org). The fourth part of the article includes the items 1-5 of ARRIVE 2.0 Recommended 11 section, which covers "Abstract" "Background" "Objectives" "Ethical statement" and "Housing and husbandry". Its aim is to promote the full understanding and use of the ARRIVE 2.0 guidelines by domestic researchers, enhance the standardization of experimental animal research and reporting, and promote the high-quality development of experimental animal technology and comparative medicine research in China.

In order to construct a recombinant replication deficient human type 5 adenovirus (Ad5) expressing a foot-and-mouth disease virus (FMDV) capsid protein, specific primers for P12A and 3B3C genes of FMDV-OZK93 were synthesized. The P12A and 3B3C genes were then amplified and connected by fusion PCR, and a recombinant shuttle plasmid pDC316-mCMV-EGFP-P12A3B3C expressing the FMDV-OZK93 capsid protein precursor P12A and 3B3C protease were obtained by inserting the P12A3B3C gene into the pDC316-mCMV-EGFP plasmid. The recombinant adenovirus rAdv-P12A3B3C-OZK93 was subsequently packaged, characterized and amplified using AdMax^TM adenovirus packaging system, and the expression was verified by infecting human embryonic kidney cell HEK-293. The humoral and cellular immunity levels of well-expressed and purified recombinant adenovirus immunized mice were evaluated. The results showed that rAdv-P12A3B3C-OZK93 could be stably passaged and the maximum virus titer reached 1×10^9.1 TCID₅₀/mL. Western blotting and indirect immunofluorescence showed that rAdv-P12A3B3C-OZK93 expressed the FMDV-specific proteins P12A and VP1 in HEK-293 cells. In addition, the PK cell infection experiment confirmed that rAdv-P12A3B3C-OZK93 could infect porcine cells, which is essential for vaccination in pigs. Comparing with the inactivated vaccine group, the recombinant adenovirus could induce higher FMDV-specific IgG antibodies, γ-IFN and IL-10. This indicates that the recombinant adenovirus has good immunity for animal, which is very important for the subsequent development of foot-and-mouth disease vaccine.
Adenoviridae/genetics* ; Adenoviruses, Human/genetics* ; Animals ; Antibodies, Viral ; Capsid/metabolism* ; Capsid Proteins ; Foot-and-Mouth Disease/prevention & control* ; Foot-and-Mouth Disease Virus/genetics* ; HEK293 Cells ; Humans ; Mice ; Recombinant Proteins/genetics* ; Serogroup ; Swine ; Viral Proteins ; Viral Vaccines/genetics*