OBJECTIVE: CRISPR-Cas protects bacteria from exogenous DNA invasion and is associated with bacterial biofilm formation and pathogenicity. METHODS: We analyzed the type I-F CRISPR-Cas system of Legionella pneumophila WX48, including Cas1, Cas2-Cas3, Csy1, Csy2, Csy3, and Cas6f, along with downstream CRISPR arrays. We explored the effects of the CRISPR-Cas system on the in vitro growth, biofilm-forming ability, and pathogenicity of L. pneumophila through constructing gene deletion mutants. RESULTS: The type I-F CRISPR-Cas system did not affect the in vitro growth of wild-type or mutant strains. The biofilm formation and intracellular proliferation of the mutant strains were weaker than those of the wild type owing to the regulation of type IV pili and Dot/Icm type IV secretion systems. In particular, Cas6f deletion strongly inhibited these processes. CONCLUSION The type I-F CRISPR-Cas system may reduce biofilm formation and intracellular proliferation in L. pneumophila.
Legionella pneumophila/pathogenicity* ; CRISPR-Cas Systems ; Biofilms/growth & development* ; Phenotype ; Bacterial Proteins/metabolism* ; Gene Deletion

Iodine speciations in aquatic environments are affected by dissolved oxygen,redox potential,microbial activity,organic matter decomposition,light reaction,etc.Accurate quantification of iodine speciation can not only help to understand the geochemical cycle of iodine,but also help to trace and study environmental processes.Based on the combination of ion chromatography(IC)and inductively coupled plasma mass spectrometry(ICP-MS),a rapid and sensitive method was established for determining the speciations of iodine in environmental water samples including seawater,river water,lake water,rainwater,groundwater,etc.The results presented here showed that IO3?and I?in seawater were quickly separated and measured within 120 s when using guard column AG22 and 8 mmol/L(NH4)2CO3 as the mobile phase.While for lake water,river water and precipitation samples with high soluble organically bond iodine(SOI),an AS22 separation column(250 mm×4 mm)connected with a guard column and using 50 mmol/L(NH4)2CO3 as mobile phase could effectively separate unknown SOI from IO3? to achieve accurate quantification of IO3?.For accurate correction of iodine measurement signal fluctuations,133Cs was directly added to the(NH4)2CO3 mobile phase as an internal standard.The SOI content was calculated by the total iodine concentrations minus the sum of IO3?and I?.The precision of the established iodine speciation analytical method was better than 3.5%,and the standard addition experiment showed that the analytical method was accurate.When the injection volume was 25 μL,the detection limits were 0.011?0.025 μg/L for IO3? and 0.023?0.031 μg/L for I?,respectively.The method was successfully used to analyze IO3?,SOI and I? in environmental water samples,such as seawater,river water,rainwater and groundwater.

Objective To study the distribution,drug resistance,and biofilm characteristics of carbapenem-resistant Acinetobacter baumannii(CRAB)isolated from hospitalized children,providing a reference for the prevention and treatment of CRAB infections in hospitalized children.Methods Forty-eight CRAB strains isolated from January 2019 to December 2022 were classified into epidemic and sporadic strains using repetitive extragenic palindromic sequence-based polymerase chain reaction.The drug resistance,biofilm phenotypes,and gene carriage of these two types of strains were compared.Results Both the 22 epidemic strains and the 26 sporadic strains were producers of Class D carbapenemases or extended-spectrum β-lactamases with downregulated outer membrane porins,harboring the VIM,OXA-23,and OXA-51 genes.The biofilm formation capability of the sporadic strains was stronger than that of the epidemic strains(P＜0.05).Genes related to biofilm formation,including Bap,bfs,OmpA,CsuE,and intI1,were detected in both epidemic and sporadic strains,with a higher detection rate of the intI1 gene in epidemic strains(P＜0.05).Conclusions CRAB strains are colonized in the hospital,with sporadic strains having a stronger ability to form biofilms,suggesting the potential for forming new clonal transmissions in the hospital.Continuous monitoring of the epidemic trends of CRAB and early warning of the distribution of epidemic strains are necessary to reduce the risk of CRAB infections in hospitalized children.[Chinese Journal of Contemporary Pediatrics,2024,26(4):358-364]

OBJECTIVES: To derive the paternity index (PI) calculation formula of the alleged father (AF) when the AF is a relative (parent/child, siblings, grandparent/grandchild, uncle/nephew, first cousins) of the child's biological mother. METHODS: For the case when the AF is related to the child's biological mother, the existence of the relationship in the numerator and denominator hypothesis of PI was considered. The genotype frequency of the AF was calculated by using the frequency formula in which the mother's genotype was considered, while the random male in the denominator was substituted as another relative of the mother's same rank. The PI calculation formula was derived to eliminate the effect of the relationship between AF and the child's biological mother. RESULTS: When the AF and the biological mother have first, second and tertiary kinship, a more conservative PI was obtained from the PI calculation formula derived in this study compared with the PI calculation method which did not consider kinship. CONCLUSIONS The calculation method provided in this study can eliminate the effect of the relation of the AF and mother on the PI in incest cases, to obtain more accurate and conservative identification conclusions.
Female ; Humans ; Male ; Child ; Paternity ; Mothers ; Genotype ; Fathers

Kidney is an essential organ in human body with multiple physiological functions. However, there is 10 % population worldwide with renal disease. It is urgent to generate a model which is more similar with kidney at structural and functional level to study renal disease. The rise of in vitro differentiation technology from pluripotent stem cells gives regeneration medicine and precise medicine new energy. This study mimics kidney development in vitro by inducing human pluripotent stem cells including embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs) into kidney progenitor cells, and further forming nephrons, which is the structure and function unit in kidney. Human pluripotent stem cells were differentiated into primitive streak through activating WNT pathway while inhibiting TGF-(B signaling. Afterward, the primitive streak spontaneously differentiated into intermediate mesoderm. Then, we induced intermediate mesoderm cells into kidney progenitor cells through FGF pathway. The FACS analysis data indicated kidney progenitor cells were up to 51. 5%-61. 9% in total cell population. Immuno-stai-ning results showed these structures contained podocytes of glomerulus, proximal tubule, and distal tubule. This kidney differentiation protocol is stable, high-efficient, and well repeatable. This research provides a novel platform for early human kidney development study, kidney disease modeling, and drug screening.

The treatment of refractory Glaucoma is a difficult problem in clinical ophthalmology. For refractory glaucoma patients with hyphema, shallow anterior chamber, anterior conglutination of peripheral chamber angle, corneal endothelium dystrophy or decompensated, at present, there is no effective treatment. In order to solve this problem, a new type posterior integral glaucoma valve with IOP control device was designed using medical titanium alloy, and the valve model was established by Abaqus software, and the stiffness and preload of the valve were analyzed by finite element method. The results showed that the opening and closing of the valve were controlled automatically by the pressure difference between the front and back of the valve, and the opening and flow rate of the valve increase dynamically with the increase of intraocular pressure, and finally reached the set ideal IOP value of steady state.
Finite Element Analysis ; Follow-Up Studies ; Glaucoma ; Glaucoma Drainage Implants ; Humans ; Intraocular Pressure ; Treatment Outcome

Objective:To establish the grade evaluation method for Codonopsis Radix slices based relative quality constants， in order to provide scientific theoretical basis for grading of Codonopsis Radix slices. Method:Through literature and market research，the main production areas of Codonopsis Radix slices were determined，and 67 batches of Ludangshen slices（52 batches） and Baitiaodang slices （15 batches） were collected. The appearance traits （average quality and average thickness of Codonopsis Radix slices） were observed and measured. According to Chinese Pharmacopoeia （2015 edition）， the extract and the content of Codonopsis pilosula polysaccharide was determined by phenol-sulphoacid method. Then the relative quality constant was calculated，and the results of grade evaluation were evaluated through systematic cluster analysis and correlation analysis. Result:Relative quality constants of 67 batches of Codonopsis Radix slices were between 0.32-2.97. If these samples were divided into three grades：the first-grade relative quality constants were greater than or equal to 2.08，the second grade was greater than or equal to 0.89 but less than 2.08，while the third grade was less than 0.89. The results of systematic cluster analysis showed that 67 batches of Codonopsis Radix slices were clustered into 3 categories，and the results were basically consistent with the classification. The correlation analysis showed a positive correlation between the content of the extracts and the polysaccharide content （P<0.05）. Conclusion:This method links the extrinsic characteristics to the intrinsic quality，and objectively grade Codonopsis Radix slices， so as to provide a basis for its grade standards.