Porcine reproductive and respiratory syndrome (PRRS), caused by the porcine reproductive and respiratory syndrome virus (PRRSV), is one of the major diseases threatening the swine industry. This study aims to rationally design and optimize natural antimicrobial peptides to identify antiviral candidates with potent inhibitory activity against PRRSV, thereby establishing a foundation for the development of novel preventive and therapeutic agents targeting PRRS. In this study, with cecropin D (CD) as the parent peptide, three derivatives (CD-2, CD-3, and CD-4) were designed through amino acid substitutions. CD and derived peptides were obtained by solid-phase peptide synthesis. MS and reversed-phase (RP)-HPLC were employed for sequence identification, purification, and purity analysis. The secondary structures of the peptides were investigated by circular dichroism spectroscopy. CellTiter 96^® AQueous one solution cell proliferation assay was used to evaluate the cytotoxicity of the peptides. The inhibitory activities and mechanisms of the peptides against PRRSV were studied by Western blotting, RT-qPCR, and indirect immunofluorescence assay. The MS and RP-HPLC results showed that CD and derived peptides were successfully synthesized, with the purity reaching up to 95%. Circular dichroism analysis revealed that the CD derivatives exhibited more stable and abundant α-helices in a cell membrane-mimicking environment. The MTS assay indicated that all tested peptides at 100 μg/mL had negligible cytotoxicity. The experimental results of the action phase of the peptide against PRRSV demonstrated that the derived peptides significantly enhanced antiviral activities at the viral entry stage compared with the parent peptide. This enhancement was attributed to the introduction of lysine, tryptophan, and phenylalanine, which increased the hydrophobicity and positive charge of the peptides. These findings provide a theoretical basis for the application and structural optimization of antiviral peptides and may offer a new strategy for preventing and controlling PRRSV.
Porcine respiratory and reproductive syndrome virus/physiology* ; Animals ; Swine ; Antiviral Agents/chemistry* ; Porcine Reproductive and Respiratory Syndrome/virology* ; Virus Internalization/drug effects* ; Antimicrobial Peptides/chemistry*

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.

OBJECTIVE:To investigate the role of clinical pharmacists in the treatment of high paraplegia patient with hospital acquired pneumonia. METHODS:Clinical pharmacists provided suggestions for anti-infective treatment failure of a high paraplegia patient with hospital acquired pneumonia,including anti-infective treatment of imipenem and cilastatin sodi-um 1.0 g,ivgtt,qid,de-escalation anti-infective treatment of cefoperazone sodium and sulbactam sodium 3.0 g,ivgtt,bid+amikacin 0.4 g,ivgtt,bid,and prevention treatment of fluconazole sodium chloride 0.2 g,ivgtt,qd against potential invasive infections with fungi,etc.,assisted physician to improve therapy plan,monitor ADR and guide rational drug use. RE-SULTS:After 3 weeks of treatment,the symptoms had been improved significantly. CONCLUSIONS:Clinical pharmacists provide individual pharmaceutical care to reduce ADR during treatment and improve the effectiveness and safety of clinical treatment.

Objective To investigate physical activities of preschool children by gender and to explore the effects of activity type on bone indexes.Methods During 2009 and 2010,397 preschool children of 3-5 years old were randomly selected from 4 kindergartens in Chengdu Province of China.Ultrasound bone analyzer was used to assess children's bone mass.A physical activity questionnaire was completed by parents to evaluate physical activities at leisure time.Student's t test and least square regression were used for data analysis.Results Concerning activity types,boys spent more leisure time on running and Wushu than girls did (t values were 1.94 and 2.84,respectively ; both P ＜ 0.05).However,girls spent more time on dancing (0.78 h),jumping rope (0.08 h) and manual labour (0.22 h) each day (t values were-9.50,-3.43 and-1.92,respectively; all P ＜ 0.05).The weekly total exercise time and energy consumption per unit of body weight of girls vs.boys were 7.29 vs.6.51 h and 127.57 vs.113.85 kJ (t values were 2.63 and 2.04,respectively ; both P ＜ 0.05).About per day time on sleeping and per week time on watching television,there were no significant difference between boys and girls (t =0.180,0.520;P ＞0.05).But boys spent more time on electronic game and computer than girls (t =0.760,2.510;P ＜ 0.05).The normalized correlation coefficient for bone mass and moderate physical activities or jumping was 0.184 and 0.275,respectively (both P ＜ 0.05).Conclusions Our data suggest that preschool children's bone volume may be positively correlated with moderate physical activities and jumping activities.Introducing some moderate physical activities or activity appliance,toys and playing fields as well as increasing professional training might be helpful.