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Genome Announcements Jan 2016We sequenced the complete genome of the highly virulent Aeromonas schubertii strain WL1483, which was isolated from diseased snakehead fish (Channa argus) in China. The...
We sequenced the complete genome of the highly virulent Aeromonas schubertii strain WL1483, which was isolated from diseased snakehead fish (Channa argus) in China. The full genome sequence of A. schubertii WL1483 is 4,400,034 bp, which encodes 4,376 proteins and contains 195 predicted RNA genes.
PubMed: 26798095
DOI: 10.1128/genomeA.01567-15 -
Fish & Shellfish Immunology Apr 2022Interleukin-21 (IL-21), a crucial immune regulatory molecule, belongs to the common γ-chain family of type I cytokines, and exerts pleiotropic effects on multiple...
Characterization of snakehead (Channa argus) interleukin-21: Involvement in immune defense against two pathogenic bacteria, in leukocyte proliferation, and in activation of JAK-STAT signaling pathway.
Interleukin-21 (IL-21), a crucial immune regulatory molecule, belongs to the common γ-chain family of type I cytokines, and exerts pleiotropic effects on multiple immune cell types in mammals. However, the characteristics and functions of fish IL-21 remain unclear. To further investigate the molecular mechanism of IL-21 in teleosts, we first cloned and identified the IL-21 gene (designated shIL-21) of the snakehead (Channa argus). The full-length open reading frame of shIL-21 is 438 bp in length, and encodes a predicted protein of 145 amino acid residues. A sequence analysis showed that shIL-21 has the typical structural characteristics of other IL-21 proteins, containing four α-helices and four conserved cysteine residues. In a phylogenetic analysis, shIL-21 clustered within a subgroup of IL-21 proteins from other teleost species and shared its closest evolutionary relationship with that of Lates calcarifer. The expression analysis showed that shIL-21 was ubiquitously expressed in all the healthy snakehead tissues tested, albeit at different levels. After infection with Nocardia seriolae or Aeromonas schubertii, the relative expression of shIL-21 was mainly upregulated in the head kidney and spleen in vivo. Similarly, after stimulation with the three pathogen analogues lipoteichoic acid, lipopolysaccharides, and polyinosinic-polycytidylic acid, the expression of shIL-21 was also induced in head kidney leukocytes in vitro. A recombinant shIL-21 protein was expressed and purified, and promoted the proliferation of head kidney leukocytes, induced the expression of genes encoding critical signaling molecules in the Janus kinase (JAK) and signal transducer and activator of transcription (STAT) pathway, including JAK1, JAK3, STAT1, and STAT3, and induced the expression of endogenous shIL-21 and genes encoding several key proinflammatory cytokines (tumor necrosis factor-α, interferon-γ, and IL-1β). Taken together, these preliminary findings suggest that shIL-21 is involved in the immune defense against bacterial infection, in leukocyte proliferation, and in the activation of the JAK-STAT pathway. They thus extend the functional studies of IL-21 in teleosts.
Topics: Animals; Cell Proliferation; Fish Diseases; Fishes; Interleukins; Janus Kinases; Leukocytes; Mammals; Phylogeny; STAT Transcription Factors; Signal Transduction
PubMed: 35278639
DOI: 10.1016/j.fsi.2022.03.006 -
Applied Microbiology and Biotechnology Nov 2019Streptococcus agalactiae is a major pathogen causing streptococcosis. To prevent and control this bacterial disease, antagonistic bacteria have become a new research...
Bacillus velezensis LF01: in vitro antimicrobial activity against fish pathogens, growth performance enhancement, and disease resistance against streptococcosis in Nile tilapia (Oreochromis niloticus).
Streptococcus agalactiae is a major pathogen causing streptococcosis. To prevent and control this bacterial disease, antagonistic bacteria have become a new research hotspot. This study evaluated the probiotic potential of Bacillus velezensis LF01 strain, which is antagonistic to S. agalactiae. The active compounds produced by LF01 showed antimicrobial activity against a broad spectrum of fish pathogens, including S. agalactiae, Streptococcus iniae, Aeromonas hydrophila, Edwardsiella tarda, Edwardsiella ictaluri, Aeromonas schubertii, Aeromonas veronii, Aeromonas jandaei, and Vibrio harveyi. The antimicrobial compounds were heat stable, pH stable, UV stable, resistant to proteases, and could be stored for a long time. To evaluate the probiotic function of LF01 in Nile tilapia, juveniles were divided into three treatment groups: a control group, an interval feeding group, and a continuous feeding group. Tilapia fed with LF01-supplemented diets (1.0 × 10 CFU/g) showed significantly better growth performances than those of the control group (P < 0.05). Tilapia fed with LF01-supplemented diets significantly increased lysozyme (LZY) and superoxide dismutase (SOD) activities. The expression of three immune-related genes (C3, lyzc, and MHC-IIβ) was higher in the intestine, head kidney, and gill of tilapia from the continuous feeding group than in those from the control group (P < 0.05). Tilapia fed with LF01-supplemented diets showed remarkably improved survival rates after S. agalactiae infection, and analysis of their intestinal tract pathogens revealed that the abundance of Edwardsiella and Plesiomonas had significantly decreased compared with the control group. Our findings demonstrate that LF01 is an effective antagonist against various fish pathogens and has potential for controlling infections by Streptococcus spp. and other pathogens in tilapia.
Topics: Animals; Antibiosis; Bacillus; Biological Control Agents; Cichlids; Fish Diseases; High-Throughput Nucleotide Sequencing; Probiotics; Streptococcal Infections; Streptococcus agalactiae
PubMed: 31654082
DOI: 10.1007/s00253-019-10176-8 -
Pediatrics International : Official... Aug 2014Bloody diarrhea in children is usually due to either infectious or inflammatory etiology, but infection is far more common than inflammatory bowel disease in children...
Bloody diarrhea in children is usually due to either infectious or inflammatory etiology, but infection is far more common than inflammatory bowel disease in children worldwide. If, however, the patient has unfavorable response to antibiotics and a definite infectious agent has yet to be identified; colonoscopy should be performed. The current patient presented with acute onset of mucous bloody diarrhea. Stool culture was initially identified as Vibrio mimicus and later identified as Aeromonas schubertii but the biochemistry did not fit well with either organism. After a prolonged course of hematochezia despite i.v. antibiotics, colonoscopy was performed that showed inflammation in the rectosigmoid area. Meanwhile, the final biochemistry tests and 16s rRNA sequencing of the organism confirmed Chromobacterium haemolyticum infection. Twelve weeks after the initial colonoscopy, repeat colonoscopy showed post-infectious colitis. Herein we report on the first pediatric case of C. haemolyticum infection causing proctocolitis.
Topics: Child, Preschool; Chromobacterium; Female; Gram-Negative Bacterial Infections; Humans; Proctocolitis
PubMed: 25252051
DOI: 10.1111/ped.12301