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The high prevalence of myopia is a global public health concern, and the risk of associated complications is becoming increasingly apprent.The International Myopia Institute (IMI) was established in 2015 to promote scientific research and clinical practice in myopia control, and IMI published the White Paper on Myopia Prevention and Control on the diagnosis, treatment, and management of myopia.In 2023, the IMI released the series three of the White Paper on Myopia Prevention and Control, which delves deeper into key issues in myopia research and management.The white paper focuses on non-pathological changes observed in axial myopia, and the role of the choroid in eye growth and myopia management.It also reviews the evidence for myopia incidence, progression and management in atypical populations, such as infants, pre-school children, and young adults.It provides recommendations and strategies for clinical practice in myopia management and summarizes important new findings in myopia research since 2019, which are summarized into the IMI 2023 Digest.This article aims to interpret the key contents of the series three of the White Paper on Myopia Prevention and Control, to help professionals involved in myopia control to stay informed about the latest evidence from international research, to optimize strategies for preventing and treating myopia-related diseases, and ultimately to promote the development of myopia research and management in China.
ABSTRACT
Objective@#To isolate a bacteriophage against pan-drug resistant Klebsiella pneumoniae in a burn patient, and to study its biological characteristics, genomic information, and effects on bacterial biofilm.@*Methods@#(1) In 2018, pan-drug resistant Klebsiella pneumoniae UA168 (hereinafter referred to as the host bacteria) solution isolated from the blood of a burn patient in Ruijin Hospital Affiliated to Shanghai Jiao Tong University School of Medicine (hereinafter referred to as Ruijin Hospital) was used to isolate and purify the bacteriophage against pan-drug resistant Klebsiella pneumoniae from the sewage of Ruijin Hospital with sewage co-culture method, drip plate method, and double-agar plate method. The bacteriophage was named as phage KP168 and the plaque morphology was observed. (2) The phage KP168 solution was taken for cesium chloride density gradient centrifugation and dialysis, and then the morphology of phage KP168 was observed through transmission electron microscope after phosphotungstic acid negative staining. (3) The phage KP168 solution was taken to determine the lytic ability of the phage KP168 against 20 strains of pan-drug resistant Klebsiella pneumoniae isolated from the burned patients′ blood in Ruijin Hospital by the drip plate method, and then the lysis rate was calculated. (4) The phage KP168 solution at a initial titer of 9.3×1011 plaque-forming unit (PFU)/mL (400 μL per tube) and the host bacteria solution at a concentration of 1×109 colony-forming unit (CFU)/mL (4 mL per tube) were conventionally shaking cultured together for 4 hours at multiplicity of infection (MOI) of 10.000, 1.000, 0.100, 0.010, or 0.001, respectively (1 tube per MOI). The titer of phage KP168 was measured by the double-agar plate method (the measurement method was the same below) to select the optimal MOI. The experiment was repeated three times. (5) The host bacteria solution at a concentration of 1×109 CFU/mL (4 mL per tube) and the phage KP168 solution at an adjusted titer of 5×107 PFU/mL (400 μL per tube) were mixed at the MOI of 0.005. The plaques were counted 0 (immediately), 1, 2, 3, 4, 5, 15, and 30 minutes (1 tube at each time point) after mixing by the double-agar plate method (the counting method was the same below), and the percentage of adsorbed phages was calculated to screen for the optimal adsorption time. The experiment was repeated three times. (6) The host bacteria solution at a concentration of 1×109 CFU/mL (300 μL per tube) and the phage KP168 solution at a titer of 5×108 PFU/mL (60 μL per tube) were mixed at MOI of 0.005 and conventionally shaking cultured after standing for the optimal adsorption time. The phage KP168 titer was measured 0 (immediately), 10, 20, 30, 40, 50, 60, 70, 80, 90, and 100 minutes after culture, and a one-step growth curve was drawn. The experiment was repeated three times. (7) The phage KP168 solution at a titer of 2.5×1010 PFU/mL was left to stand for 1 hour at 37, 40, 50, 60, or 70 ℃ (3 tubes at each time point, 1 mL per tube) for counting the plaques, and then the thermal stability curve was drawn. SM buffer at a pH values of 5.0, 6.0, 7.0, 7.4, 8.0, 9.0, or 10.0 were added to the phage KP168 solution at a titer of 3.0×1010 PFU/mL, respectively. The mixed solution was left to stand for 1 hour at 37 ℃ (3 tubes of each pH, each tube containing 100 μL phage KP168 solution and 900 μL SM buffer), and then the plaques were counted, and an acid-base stability curve was drawn. (8) The phage KP168 solution was taken for DNA extraction and sequencing after dialysis as in experiment (2). The whole genome was annotated with Prokka to obtain the coding sequence of phage KP168. Nucleotide′s BLAST function was used to proceed nucleic acid sequence alignment for finding a known phage with the highest similarity to the phage KP168 nucleic acid sequence, and Blastx function was used to translate the coding sequence into protein for its function prediction. The comparison with Antibiotic Resistance Genes Database and Virulence Factors Database was proceeded. (9) In a 96-well plate, at a MOI of 1.000, 0.100, 0.010 or 0.001 (3 wells per MOI), 20 μL phage KP168 solution at a initial titer of 5.8×1010 PFU/mL was added to 200 μL host bacteria solution at a concentration of 1.5×108 CFU/mL (the same concentration below) for co-cultivation for 48 hours. After 200 μL host bacteria solution was left to stand for 48 hours, 20 μL phage KP168 solution at a titer of 1×106, 1×107, 1×108, 1×109, or 1×1010 PFU/mL (3 wells per titer) was added respectively for action for 4 hours. In both experiments, 200 μL host bacteria solution added with 20 μL SM buffer (3 wells) acted as a negative control, and 220 μL LB culture medium (3 wells) acted as a blank control. Absorbance values were measured by a microplate reader, and inhibition/destruction rates of biofilm were calculated. The experiments were both repeated three times.@*Results@#(1) The plaques of phage KP168 successfully isolated and purified were transparent and round, and its diameter was approximately 1.5 mm. (2) The phage KP168 has a regular polyhedron structure with a diameter of about 50 nm and without a tail. (3) The phage KP168 could lyse 13 of 20 strains of Klebsiella pneumoniae from burned patients, with a lysis rate of 65.0%. (4) When MOI was 1.000, the titer was the highest after co-culturing the phage KP168 with the host bacteria for 4 hours, which was the optimal MOI. (5) After the mixing of the phage KP168 with the host bacteria for 4 minutes, the percentage of the adsorbed phage reached the highest, which was the optimal adsorption time. (6) The one-step growth curve showed that during the lysis of the host bacteria by phage KP168, the incubation period was about 10 minutes, and the lysis period was about 40 minutes. (7) With the condition of 40 ℃ or pH 7.4, the number of plaques and the activity of phage KP168 reached the highest. (8) The genome of phage KP168 was a linear double-stranded DNA with a length of 40 114 bp. There were 48 possible coding sequences. It had the highest similarity to Klebsiella phage_vB_Kp1. The most similar known proteins corresponding to the translated proteins of coding sequences contained 23 hypothetical proteins and 25 proteins with known functions. No resistance genes or virulence factor genes were found. The GeneBank accession number was KT367885. (9) After 48 hours of co-cultivation of the phage KP168 and the host bacteria at each MOI, the inhibition rates of biofilm were similar, with an average of about 45%. After the phage KP168 with a titer of 1×109 PFU/mL acted on the biofilm formed by the host bacteria for 4 h, the destruction rate of biofilm was the highest, reaching an average of 42%.@*Conclusions@#In this study, a bacteriophage against pan-drug resistant Klebsiella pneumoniae from a burn patient, phage KP168, is isolated from sewage, which belongs to the tailless phage. It has a wide host spectrum, short adsorption time, and short incubation period, with certain thermal and acid-base stability. Its genomic information is clear, and it does not contain resistance genes or virulence factor genes. It also has an inhibitory effect on the formation of bacterial biofilm and a destructive effect on the formed bacterial biofilm.
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BACKGROUND: The purpose of this study was to introduce the mechanism and clinical application of muscular atrophy that is a hotspot in the 65th Annual Meeting of American College of Sports Medicine and the 9th World Conference on Exercise Is Medicine and the World Conference of Basic Science of Muscle Hypertrophy and Atrophy. OBJECTIVE: To summarize and analyze the frontiers and hotspots of research findings on muscular atrophy, in order to provide new ideas for further research of exercise improving muscle function and the mechanism and application in this field, and provide a reference for the study on sports science, sports medicine, and sports rehabilitation in China. METHODS: Related reports and cutting-edge research findings in 65th Annual Meeting of American College of Sports Medicine were collected. Meanwhile, PubMed database between January 1993 and August 2018 was retrieved. The keywords were "skeletal muscle, muscle atrophy, movement and muscle, resistance movement". Thirty-five articles related to the molecular mechanism and clinical application of muscle atrophy were included for analysis and discussion. RESULTS AND CONCLUSION: The World Congress is a unique opportunity to bring together interdisciplinary investigators for the most comprehensive meeting ever held on this topic. The program will include a keynote lecture, tutorials, and symposia from leading experts. The meeting focused on the intrinsic and extrinsic variables that regulate skeletal muscle hypertrophy and atrophy. How exercise brings about skeletal muscle atrophy and its application in clinical problems such as aging, disease, injury, chronic diseases, and how these changes may relate to chronic disease were discussed as well. The research on muscle hypertrophy is mostly concentrated in the field of competitive sports.