| The frog taro disease is a kind of frog disease with head falsification,cataracts of the eyeball,and dyskinesia as typical symptoms.The disease has a high mortality rate,spread rapidly,occurs year after year,and has poor drug use.It poses a serious threat to frogs.Class aquaculture.Different researchers isolated at least 9 virulence-producing bacteria from diseased frogs with such symptoms,among which Elizabethkingia meningoseptica is most common.In this study,a gram-negative bacillus was isolated from the brain,eyeball,liver,ovary and other tissues of the frogs of the typhoid frog in Yueyang,Hunan Province.The pathogenicity of the bacterium was confirmed by regression tests.Physiological and biochemical characteristics,16 s rDNA gene construction phylogenetic tree and other traditional methods,the author believes that it is meningococcal septicemia Elizabethus,but after the whole genome sequencing,the genomic data compared to species identification of Non-Redundant Protein Database,confirmed its It is Elizabethkingia miricola.Scanning electron microscopy observations of this bacterium showed that the surface of the bacteria often had a depression.Bridges were connected between different bacteria.The average size of the bacteria was 1.72±0.6 μm×0.48±0.7 μm.The cells were clearly visible under transmission electron microscope.Three floors.Pathogens entered the plateau phase at 17 h in BHI liquid medium at 28° C.and 160 r/min.The pathogen is sensitive to seven drugs: Mefose,Streptomycin,Doxycycline,Azithromycin,Midecamycin,Florfenicol,and Rifafim.Histopathological observations of natural pathological frogs showed that hepatocytes were swollen,many vacuoles appeared,degeneration and necrosis;epicardial inflammation;mild cerebral edema,inflammatory lesions;depolarization and lysis of cones of the eye rod;other tissues No obvious abnormality.This is the histopathological basis of sick frog taro,movement disorders,and cataracts.Finally,this study performed genome-wide sequencing and analysis of the strain of Elizabeth miRNA isolate HNW1681,summarized the basic situation of its genome,and tapped its genetic information on pathogen survival,pathogenicity,resistance production,evolution,and many other aspects.Select the focus to make a preliminary interpretation.Through the above studies,we confirmed that M.elegans was the pathogen that caused this black spot frog taro disease.The traditional identification method could not clearly distinguish between mil Elizabeth and meningococcal septicemia.We reported for the first time the transmission electron microscopy and scanning electron microscopy observations of this strain.Through the combined interpretation of gross symptoms and pathological observations,we described the different degrees of pathological changes in the heart,liver,brain,and eyes,and revealed the pathological basis of various symptoms of the disease.The pathogenic properties revealed in the genome study further revealed the pathogenic mechanism of the pathogen. |
