ABSTRACT
Objective:To analyze the biological characteristics, phylogenic features and clinical significance of SQ219 and SQ220 isolated from clinical sputum and midstream urine specimens.Methods:The culture and biochemical characteristics of the two strains were observed. VITEK2 System, drug sensitivity testing and MALDI-TOF mass spectrometry were used for bacterial identification. Phylogenetic analysis based on 16S rRNA and core genome was performed. The average nucleotide identity (ANI) based on whole genome sequences was calculated.Results:SQ219 and SQ220 were Gram-stain-negative, aerobic, catalase- and oxidase-positive, and non-motile bacteria. Their optimum growth was observed in NaCl-free medium at 30℃ and pH7. Flexirubin-type pigments were produced by SQ220 on Colombia blood agar, but not by SQ219. Both SQ219 and SQ220 were resistant to aztreonam, amikacin, tobramycin and colistin, which was consistent with the drug resistance phenotype of genus Chryseobacterium. The genome sequences of SQ219 and SQ220 were 5.08 Mb and 4.80 Mb in length, and the G+ C contents were 36.72% and 36.36%, respectively. Both strains carried β-lactam resistance gene ( blaCGA). 16S rRNA phylogenetic analysis showed that SQ219 and SQ220 were closely related to Chryseobacterium gambrini DSM18014 T with the similarities of 98.93% and 98.36%, respectively. Core genome phylogenetic analysis revealed that SQ219 and SQ220 were highly homologous to Chryseobacterium gambrini DSM18014 T. However, the ANI values between the two strains and Chryseobacterium gambrini DSM18014 T were 92.49% and 93.27%, respectively, below the threshold for prokaryotic species identification. Conclusions:Based on the phenotypic and phylogenetic data, SQ219 and SQ220 represent a novel species of the genus Chryseobacterium. This study would help promote the understanding of the evolution of Chrysobacterium and provide reference for the identification of new species of Chrysobacterium.
ABSTRACT
Objective To explore the mechanism of protection role of ambroxol against acute lung injury (ALI)by studying the change of cytokine mRNA expression during the course of ALI.Method The study was composed of experiments both in vivo and in vitro. (1)Experiments in vivo were as follows.Twenty-four sprague-Dawley rats were randomly divide into 3 groups,namely,control group(n=8),acute lung injury group(LPS group,n=8)and ambroxol group(LPS+A group,n=8).The rat model of acute lung injury was induced by intraperitoneal injection of 10 mmol/L lipoopolysaccharide(LPS).The pathological alteration of lung tissue and arterial partial pressure of oxygen(PaO2)were observed.Expressions of TNF-α,IL-10 and IL-24 mRNA were determined by using RT-PCR assay. (2)Experiments in vitro were the followings.Alveolar macrophage cells were collected and divided into 3 groups as above mentioned.Cells were treated with normal saline,with LPS,and with LPS plus ambroxolin dose of 180 μmol/L at 0,6,12 and 24 hours after exposure of LPS,respectively,in 3 groups as above stated.The expressions of TNF-α,IL-10 and IL-24 mRNA were also determine by using RT-PCR.Results The pathological changes of could be parially ameliorated by giving ambroxol.Massive hemorrhage along with vascular edema and infiltration occurred in the lungs of ALT rats.The pathological alterations in ALI rats treated with ambroxol were less severe.The expressions of TNF-α,IL-10 and IL-24 mRNA were dramatically increased in ALI rats,and were partially attenuated after treatment of ambroxol.Macrophages oxposed to LPS for 6 hours showed dramatical increase in expressions of TNF-α,IL-10 and IL-24mRNA those remained at high levels afterwards.The expressions of TNF-α,IL-10 and IL-24 mRNA in macrophages after exposure to both LPS and ambroxol were increased less than those exposed to LPS alone.Conclusions Ambroxol can partially ameliorate the expressions of TNF-α,IL-10 and IL-24 mRNA in alveolar macrophage induced by LPS.