This study was aimed at identifying the pathogenic bacteria responsible for the death of a young tiger at the Fujian Meihua Mountain South China Tiger Breeding Research Institute.Tissue samples from the lungs,liver,and intestines of the deceased tiger were collected,and the bacteria were cultured inasterile environment.The bacterial strains were characterized according to their morphological and molecular biological properties,including assessment of virulence genes and antibiotic resistance genes,mouse lethality tests,and antibiotic susceptibility evaluations.A predominant bacterial strain isolated from the liver of the deceased tiger was identified as enterotoxigenic Escherichia coli(ETEC)strain Tiger22513F.Phylogenetic analysis of the 16S rRNA gene revealed that the Tiger22513F strain exhibited close genetic similarity to the reference strain ETEC(MF919609.1),with 99.9%nucleotide similarity,and resided on the same evolutionary branch.The Tiger22513F strain contained 11 antibiotic resistance genes(tetA,sul1,sul3,cmlA,floR,blaTEM,blaSHV,blaCMY-2,qnrA,qnrS,and qnrD)along with five virulence genes(VT1,fyuA,tsh,iucD,and ST).Mouse lethality tests indicated significant pathogenicity toward mice,affecting primarily the lungs,liver,and intestines.Antibiotic susceptibility testing demonstrated that this strain exhibited resistance to various classes of beta-lactam antibiotics,as well as quinolones and aminoglycosides.This investigation successfully isolated a multi-drug resistant enterotoxigenic Escherichia coli strain with pronounced pathogenicity from the liver of a deceased tiger;thus providing valuable scientific insights for clinical diagnosis,as well as prevention and control measures,against ETEC infections in South China tigers.

This study was aimed at identifying the pathogenic bacteria responsible for the death of a young tiger at the Fujian Meihua Mountain South China Tiger Breeding Research Institute.Tissue samples from the lungs,liver,and intestines of the deceased tiger were collected,and the bacteria were cultured inasterile environment.The bacterial strains were characterized according to their morphological and molecular biological properties,including assessment of virulence genes and antibiotic resistance genes,mouse lethality tests,and antibiotic susceptibility evaluations.A predominant bacterial strain isolated from the liver of the deceased tiger was identified as enterotoxigenic Escherichia coli(ETEC)strain Tiger22513F.Phylogenetic analysis of the 16S rRNA gene revealed that the Tiger22513F strain exhibited close genetic similarity to the reference strain ETEC(MF919609.1),with 99.9%nucleotide similarity,and resided on the same evolutionary branch.The Tiger22513F strain contained 11 antibiotic resistance genes(tetA,sul1,sul3,cmlA,floR,blaTEM,blaSHV,blaCMY-2,qnrA,qnrS,and qnrD)along with five virulence genes(VT1,fyuA,tsh,iucD,and ST).Mouse lethality tests indicated significant pathogenicity toward mice,affecting primarily the lungs,liver,and intestines.Antibiotic susceptibility testing demonstrated that this strain exhibited resistance to various classes of beta-lactam antibiotics,as well as quinolones and aminoglycosides.This investigation successfully isolated a multi-drug resistant enterotoxigenic Escherichia coli strain with pronounced pathogenicity from the liver of a deceased tiger;thus providing valuable scientific insights for clinical diagnosis,as well as prevention and control measures,against ETEC infections in South China tigers.

OBJECTIVETo prepare quercetin nanostuctured lipid carriers (QT-NLC), and detect their physicochemical properties.

METHODQT-NLC was prepared by emulsification ultrasonic dispersion method, and the optimum prescription was screened out by orthogonal design. Transmission electron microscope was used to observe QT-NLC morphology. Granulometer was applied to determine zeta potential, particle size and distribution. DSC was adopted for phase analysis. Centrifugal ultra-filtration method was used to determine entrapment efficiency. Dialysis method was adopted to detect drug release in vitro of preparations.

RESULTQT-NLC prepared under optimum conditions was mostly spherical grains, with the average particle size of (175 +/- 25) nm, which were distributed evenly, and zeta potential was (-23 +/- 0.3) mV. DSC results indicated that the drug was dispersed in nano-particles in a non-crystalline state, with an entrapment efficiency of (95.43 +/- 0.23)% and a drug-loading capacity of (2.38 +/- 0.24)%. The in vitro drug release was 32.2% in 2 hours, which was followed by a sustained release.

CONCLUSIONEmulsification ultrasonic dispersion method is applicable for preparing QT-NLC, as nano-particles are distributed evenly, with good reliability. This processing technology is safe, reliable and highly reproducible.

Delayed-Action Preparations ; Drug Carriers ; Emulsions ; Lipids ; chemistry ; Nanoparticles ; chemistry ; ultrastructure ; Particle Size ; Quercetin ; chemistry

Objective To evaluate effects of soles with different hardness on kinematic parameters of human lower extremity during walking by conducting kinematic analysis on subjects walking with soles of different hardness. Methods Subjects were required to wear 3 kinds of shoes with soles of different hardness and walk on the treadmill at the speed of 6 km/h. Vicon infrared camera system was used to capture the motions of subjects during walking, and kinematic parameters such as heel height, toe height, knee angle and ankle angle were collected for experimental analysis. Results Compared with the other shoes, the gait cycle was increased when subjects wearing soft-soled shoes, with the smallest angel of the forward pendulum of crus. The forward pendulum of thigh was the smallest and the back pendulum was the largest when subjects wearing medium-hardness shoes. The forward pendulum of thigh was the largest and the back pendulum was the smallest when subjects wearing hard-soled shoes. The time of swing phase was relatively stable. Conclusions Soft-soled shoes are more suitable for slow walking during a short period, while medium-hardness shoes have the smallest impact on lower extremity kinematics during walking for a long period, and hard-soled shoes are suitable for fast walking during a short period.